Exam Ref 70-342 Advanced Solutions of Microsoft

Exam Ref 70-342 Advanced Solutions of Microsoft
Exam Ref 70-342
Advanced Solutions of
Microsoft Exchange
Server 2013
Brian Reid
Steve Goodman
PUBLISHED BY
Microsoft Press
A Division of Microsoft Corporation
One Microsoft Way
Redmond, Washington 98052-6399
Copyright © 2015 by Brian Reid and Steve Goodman
No part of the contents of this book may be reproduced or transmitted in any form or by any means without
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ISBN: 978-0-7356-9741-6
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Contents at a glance
Introductionxv
Preparing for the exam
CHAPTER 1
Configure, manage, and migrate Unified Messaging CHAPTER 2
Design, configure, and manage site resiliency CHAPTER 3
Design, configure, and manage advanced security
CHAPTER 4
Configure and manage compliance,
archiving, and discovery solutions
CHAPTER 5
xix
1
65
133
203
Implement and manage coexistence,
hybrid scenarios, migration, and federation
279
Index359
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Contents
Introduction
xv
Microsoft certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Free ebooks from Microsoft Press. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi
Microsoft Virtual Academy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Errata, updates, & book support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
We want to hear from you . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Stay in touch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Preparing for the exam
xix
Chapter 1: Configure, manage, and migrate Unified Messaging
Understanding Unified Messaging 1
2
Objective 1.1: Configure Unified Messaging (UM). . . . . . . . . . . . . . . . . . . . . 4
Configuring an IP gateway
4
Configuring the UM call router
9
Creating and configuring an auto attendant
12
Configuring a call answering rule
18
Designing Unified Messaging for high availability
21
Create a dial plan
23
Objective summary
26
Objective review
26
Objective 1.2: Manage Unified Messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Assigning a dial plan to a user
27
Moving users between dial plans
28
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v
Enabling and disabling UM features for a user
29
Setting up protected voice mail
33
Configuring UM mailbox policy
35
Managing UM language packs
38
Objective summary
41
Objective review
41
Objective 1.3: Troubleshoot Unified Messaging. . . . . . . . . . . . . . . . . . . . . . 42
Troubleshooting and configuring mutual Transport Layer
Security (MTLS)
43
Monitoring calls and call statistics
48
Troubleshooting and configuring Quality of Service
51
Troubleshooting SIP communication
53
Objective summary
54
Objective review
55
Objective 1.4: Migrate Unified Messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Prepare to migrate
56
Planning a migration strategy
57
Planning a coexistence strategy
58
Moving UM mailboxes between sites
58
Redirecting the SIP gateway to Exchange
59
Decommissioning the legacy system
59
Objective summary
60
Objective review
60
Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
vi
Contents
Objective 1.1: Thought experiment
61
Objective 1.1: Review
61
Objective 1.2: Thought experiment
62
Objective 1.2: Review
62
Objective 1.3: Thought experiment
63
Objective 1.3: Review
63
Objective 1.4: Thought experiment
63
Objective 1.4: Review
64
Chapter 2: Design, configure, and manage site resiliency
65
Objective 2.1: Manage a site-resilient Database Availability Group (DAG). . . 65
Planning and implementing Datacenter Activation
Coordination (DAC)
66
Given customer node requirements, recommend quorum options 72
Planning cross-site DAG configuration and configuring
DAG networks
80
Objective summary
86
Objective review
87
Objective 2.2: Design, deploy, and manage a site-resilient CAS solution. . . . 88
Planning site-resilient namespaces
88
Configuring site-resilient namespace URLs
91
Performing steps for site rollover
94
Planning certificate requirements for site failovers
94
Predicting client behavior during a rollover
96
Objective summary
100
Objective review
101
Objective 2.3: Design, deploy, and manage site resilience for transport . . 101
Configuring MX records for failover scenarios
102
Managing resubmission and reroute queues
107
Planning and configuring send/receive connectors
for site resiliency
111
Performing steps for transport rollover
112
Objective summary
115
Objective review
115
Objective 2.4: Troubleshoot site-resiliency issues. . . . . . . . . . . . . . . . . . . . 116
Resolving quorum issues
117
Troubleshooting proxy and redirection issues
118
Troubleshooting client connectivity
119
Troubleshooting mail flow
119
Troubleshoot datacenter activation
123
Troubleshooting DAG replication
124
Objective summary
126
Objective review
126
Contents
vii
Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Objective 2.1: Thought experiment
127
Objective 2.1: Review
127
Objective 2.2: Thought experiment
128
Objective 2.2: Review
128
Objective 2.3: Thought experiment
129
Objective 2.3: Review
130
Objective 2.4: Thought experiment
131
Objective 2.4: Review
131
Chapter 3: Design, configure, and manage advanced security
133
Objective 3.1: Select an appropriate security strategy. . . . . . . . . . . . . . . . 133
Evaluating role-based access control (RBAC)
134
Evaluating BitLocker
138
Evaluating smart cards
142
Evaluating Information Rights Management (IRM)
144
Evaluating S/MIME
145
Evaluating Domain Secure/TLS
155
Objective summary
162
Objective review
163
Objective 3.2: Deploy and manage IRM with Active
Directory Rights Management Services (AD RMS). . . . . . . . . . . . . . . . 164
Creating an AD RMS template
165
Creating transport protection rules
169
Creating Outlook protection rules
172
Configuring transport decryption
174
Configuring IRM for discovery
176
Configuring pre-licensing for client access
177
Objective summary
178
Objective review
179
Objective 3.3: Configure and interpret mailbox and
administrative auditing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
viii
Contents
Configuring mailbox audit logging
180
Configuring administrative audit logging
181
Interpreting all audit logs
182
Objective summary
185
Objective review
186
Objective 3.4: Troubleshoot security-related issues. . . . . . . . . . . . . . . . . . 186
Determining certificate validity
187
Ensuring proper Certificate Revocation List (CRL)
access and placement
189
Ensuring private key availability
192
Troubleshooting failed IRM protection
194
Troubleshooting RBAC
195
Objective summary
196
Objective review
197
Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Objective 3.1: Thought experiment
198
Objective 3.1: Review
198
Objective 3.2: Thought experiment
199
Objective 3.2: Review
200
Objective 3.3: Thought experiment
200
Objective 3.3: Review
200
Objective 3.4: Thought experiment
201
Objective 3.4: Review
201
Chapter 4: Configure and manage compliance, archiving,
and discovery solutions
203
Objective 4.1: Configure and manage an archiving solution. . . . . . . . . . 203
Setting up online archiving (Office 365)
205
Creating archive policies
216
Setting up on-premises archiving
220
Planning storage for an archiving solution
220
Objective summary
221
Objective review
222
Objective 4.2: Design and configure Data Loss Prevention
(DLP) solutions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Setting up pre-built rules
223
Setting up custom rules
227
Designing a DLP solution to meet business requirements
231
Contents
ix
Setting up custom policies
231
Objective summary
233
Objective review
234
Objective 4.3: Configure and administer Message
Records Management (MRM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Designing retention policies
234
Configuring retention policies
236
Creating and configuring custom tags
237
Assigning policies to users
239
Configuring the Managed Folder Assistant
240
Removing and deleting tags
241
Objective summary
243
Objective review
244
Objective 4.4: Perform eDiscovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Planning and delegating RBAC roles for eDiscovery
245
Enabling a legal/litigation hold
246
Performing a query-based In-Place Hold
247
Designing and configuring journaling
249
Performing multi-mailbox searches in Exchange
Administration Center (EAC)
254
Evaluating how to integrate In-Place federated searches
with Microsoft SharePoint
257
Objective summary
259
Objective review
259
Objective 4.5: Implement a compliance solution. . . . . . . . . . . . . . . . . . . . 260
Designing and configuring transport rules for ethical walls
260
Configuring MailTips
264
Creating, configuring, and deploying message classifications
266
Designing and configuring transport rules to meet
specified compliance requirements
268
Objective summary
271
Objective review
271
Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
x
Contents
Objective 4.1: Thought experiment
272
Objective 4.1: Review
272
Objective 4.2: Thought experiment
273
Objective 4.2: Review
273
Objective 4.3: Thought experiment
274
Objective 4.3: Review
274
Objective 4.4: Thought experiment
275
Objective 4.4: Review
275
Objective 4.5: Thought experiment
276
Objective 4.5: Review
276
Chapter 5: Implement and manage coexistence, hybrid
scenarios, migration, and federation
279
Objective 5.1: Establish coexistence with Exchange Online . . . . . . . . . . . 280
Deploying and managing hybrid configuration
280
Evaluating limitations of the Hybrid Configuration Wizard
291
Configuring requirements for single sign-on (SSO)
293
Designing and configuring Active Directory Federation
Services (AD FS)
295
Objective summary
304
Objective review
304
Objective 5.2: Deploy and manage Exchange federation. . . . . . . . . . . . . 305
Managing federation trusts with Microsoft federation gateway
306
Managing sharing policies
309
Designing certificate and firewall requirements
316
Managing organization relationships
316
Objective summary
318
Objective review
319
Objective 5.3: Implement on-premises coexistence with
legacy systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
Planning namespaces for coexistence
320
Configuring proxy redirect
323
Planning firewall configuration for coexistence
323
Planning for mail flow requirements
325
Objective summary
326
Objective review
327
Contents
xi
Objective 5.4: Set up a cross-forest coexistence solution. . . . . . . . . . . . . 327
Setting up cross-forest availability
328
Designing certificate and firewall requirements
330
Setting up cross-forest mail flow
330
Designing and configuring AutoDiscover 331
Setting up shared namespaces
333
Objective summary
337
Objective review
337
Objective 5.5: Migrate legacy systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
Determining transition paths to Exchange
338
Migrating public folders
339
Migrating mailboxes
341
Upgrading policies
343
Planning to account for discontinued features
343
Transitioning and decommissioning server roles
344
Objective summary
345
Objective review
345
Objective 5.6: Troubleshoot issues associated with hybrid
scenarios, coexistence, migration, and federation. . . . . . . . . . . . . . . . . 346
Troubleshooting transport 347
Troubleshooting Exchange federation trust and
organization relationships 348
Troubleshooting SSO/AD FS
349
Troubleshooting DirSync
349
Troubleshooting cross-forest availability
350
Objective summary
351
Objective review
351
Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
xii
Contents
Objective 5.1: Thought experiment
351
Objective 5.1: Review
352
Objective 5.2: Thought experiment
353
Objective 5.2: Review
353
Objective 5.3: Thought experiment
354
Objective 5.3: Review
354
Objective 5.4: Thought experiment
355
Objective 5.4: Review
355
Objective 5.5: Thought experiment
356
Objective 5.5: Review
356
Objective 5.6: Thought experiment
357
Objective 5.6: Review
357
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Contents
xiii
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Introduction
M
ost Exchange Server books take the view of telling how to complete each task. For the
designer of Exchange Server organizations, this is not sufficient. This is why there is both
an exam on how to complete tasks, and also a second exam on why to complete tasks. This
book covers the objective domain of Microsoft Exam 70-342, and the ”why” for why you would
do something in the product, as well as some of the ”how” for the more in-depth features.
This book covers every exam objective, but it does not cover every exam question. Only
the Microsoft exam team has access to the exam questions themselves and Microsoft regularly adds new questions to the exam, making it impossible to cover specific questions. You
should consider this book a supplement to your relevant real-world experience and other
study materials. If you encounter a topic in this book that you do not feel completely comfortable with, use the links you’ll find in text to find more information and take the time to
research and study the topic. Great information is available on MSDN, TechNet, and in blogs
and forums.
Microsoft certifications
Microsoft certifications distinguish you by proving your command of a broad set of skills and
experience with current Microsoft products and technologies. The exams and corresponding
certifications are developed to validate your mastery of critical competencies as you design
and develop, or implement and support, solutions with Microsoft products and technologies
both on-premises and in the cloud. Certification brings a variety of benefits to the individual
and to employers and organizations.
MORE INFO ALL MICROSOFT CERTIFICATIONS
For information about Microsoft certifications, including a full list of available certifications, go to http://www.microsoft.com/learning/en/us/certification/cert-default.aspx.
Acknowledgments
It is not an easy effort writing a book on Exchange Server. As you can probably guess from
the scope of the chapter headings, this book for Microsoft Exam 70-342 covers a large portion of Exchange Server and Exchange Online in Office 365. It is therefore not possible to
write a book that covers this data, though some of it is similar to that in Exchange Server
Introduction xv
2010, by far a lot has changed subtly and also in detail. That is not including Office 365, and
specifically here, the pieces on Exchange Online and Office 365. This appears to change
daily, and although it is not that frequent, there will be bits of this book that may well work
differently from between when we wrote it and when you read it—that is the effect of cloud
computing.
There are many people that are involved with writing a book, not least I would like to start
with thanking Steve Goodman my co-author, and Nicolas Blank my co-director at NB Consult
whose idea it was that I should write this book and not the one for Exam 341! Paul Robichaux
and Bhargav Shukla are writing the book for 70-341, so that at least there is a pair of these
books for both exams! I would also like to thank Andrew Higginbotham for his technical
review and his BBQ, Ashley Poxon for reading early chapter proofs for me, and for the help
from various MVPs, including Justin Harris.
But finally, and most importantly, I would like to thank Jenny my wife, for the evenings lost
writing, sorry! For your support and care, thanks! For the love you give me in modeling our
savior Christ, my love back.
—Brian Reid
I’d like to mirror Brian’s sentiments and thank my fellow MVPs who have supported both
the writing and editing of this book, along with Microsoft Press. In particular I’d like to thank
Brian Reid my co-author, Paul Robichaux for recommending me to Microsoft Press, and Karen
Szall for her support and patience.
Finally, I’d like to thank my family—my wife Lisa for putting up with the many nights taken
up writing, and my daughters Isabelle and Olivia for constantly reminding me of what’s really
important. Last but not least, I’d like to thank my father for reading every book I write cover
to cover, whether he understands it or not!
—Steve Goodman
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Introduction xvii
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Preparing for the exam
Microsoft certification exams are a great way to build your resume and let the world know
about your level of expertise. Certification exams validate your on-the-job experience and
product knowledge. Although there is no substitute for on-the-job experience, preparation
through study and hands-on practice can help you prepare for the exam. We recommend
that you augment your exam preparation plan by using a combination of available study
materials and courses. For example, you might use the Exam ref and another study guide for
your ”at home” preparation, and take a Microsoft Official Curriculum course for the classroom
experience. Choose the combination that you think works best for you.
Note that this Exam Ref is based on publicly available information about the exam and the
author’s experience. To safeguard the integrity of the exam, authors do not have access to the
live exam.
Introduction xix
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CHAPTER 2
Design, configure, and
manage site resiliency
E
mail services are typically mission critical to most businesses, so knowing how to design,
configure, and manage Exchange Server 2013 for redundancy across multiple locations is
a key requirement of the Exchange Server “IT Pro” type of administrator. Getting the design
correct is of the first consideration, because you will have issues in the configuration and
management of the service across multiple sites if it is not designed correctly.
This chapter discusses the features and roles of Exchange Server 2013 that are utilized
in a resilient site design so that you can be sure you have a solid understanding of the
requirements of the software, and so that your network, servers, and processes will work as
required.
Objectives in this chapter:
■■
Objective 2.1: Manage a site-resilient Database Availability Group (DAG)
■■
Objective 2.2: Design, deploy, and manage a site-resilient CAS solution
■■
Objective 2.3: Design, deploy, and manage site resilience for transport
■■
Objective 2.4: Troubleshoot site-resiliency issues
Objective 2.1: Manage a site-resilient Database
Availability Group (DAG)
The Database Availability Group is a collection of up to 16 Exchange Server 2013 servers
with the Mailbox Role installed that may or may not also have the Client Access Server (CAS)
role installed. The mailbox database located on any one of these servers can be replicated
onto one or more other remaining servers.
Understanding DAGs is a key requirement of the IT pro in designing Exchange Server
solutions, and it is a key objective of this exam. This exam will concentrate its questions on
the site-resiliency aspect of DAGs, and not the initial configuration of a DAG or its mailbox
databases since that is covered in exam 70-341.
65
This objective covers how to:
■■
Plan and implement Datacenter Activation Coordination (DAC)
■■
Given customer node requirements, recommend quorum options
■■
Plan cross-site DAG configuration; configure DAG networks
Planning and implementing Datacenter Activation
Coordination (DAC)
Datacenter Activation Coordination (DAC) mode is a setting that you make on a DAG’s configuration that is designed to prevent split-brain conditions at the database level, in a scenario in
which you’re restoring service to a primary datacenter after a datacenter switchover has been
performed.
A split-brain condition is where a single DAG is operating in two (or more) locations, is not
communicating across a shared link, and has mounted the same database in both locations.
In both locations, Exchange Server is making changes to the mailboxes in the database. It
could be that the owner of the mailbox has successfully logged in and is sending emails on
one active copy, or it could be that the server has mounted the database in the site where
emails from the internet arrive and so is adding new emails to the same mailbox, but in a different active copy of the same database.
There can only be one active copy of a mailbox database at any given time within a DAG.
Typically the database is active in the primary site for the DAG, and there are passive copies in the primary site and in any secondary site. Changes that happen to a given database
are logged into the same database’s transaction logs, and these logs are copied to the other
servers where they are replayed into the passive database. When all is operating correctly, the
changes are happening on only one database, the active database, and these same changes
are identically repeated on all passive copies.
In a split-brain scenario both databases are making independent changes to their copy
of the database, and the only way to resolve this is to delete one or more copies, leaving
only one active database and any database that remained in a passive state. Any database,
that also though it was active, will need to be removed. This removed copy will need to be
re-added & re-seeded; making it a passive copy once again. Seeding a database is heavy on
a network link and can be time consuming. This entire process will result in the loss of any
changes/additions of data that occurred on this unintentionally activated copy. Therefore, it is
important to avoid a split-brain condition.
To ensure that only one copy of a database will be mounted, and avoid split brain, Exchange Server uses the Datacenter Activation Coordination Protocol (DACP) as a way to communicate with other Exchange Servers in the DAG, and to determine if each server has the
rights to mount its databases or not regardless of whether the rules of cluster quorum would
determine that it has majority.
66
Chapter 2
Design, configure, and manage site resiliency
DAG scenario without Datacenter Activation Coordination enabled
The DAC property is not enabled by default, so consider this scenario where you have two
servers in the primary datacenter and the witness server (a total of three votes in the primary
datacenter), and a second datacenter that contains two other servers. In the event of a full
outage at the primary datacenter, the two DAG members and the witness server go offline.
The IT department restores service in the secondary datacenter (by forcing quorum on the
surviving nodes in the cluster), and the databases are mounted in the secondary datacenter.
The reason for the outage in the primary datacenter goes away and the servers restart.
All three servers (two DAG members and the witness server) come online, but the WAN to
the secondary datacenter does not come up (as is typical in outages involving power loss).
In the primary datacenter the Exchange Servers see that they have quorum (three votes out
of five voting members) and so mount their databases. But the databases in the secondary
datacenter are also mounted, and so changes can occur to two copies of the same database
(split-brain).
DAG scenario with Datacenter Activation Coordination enabled
Though the DAC property of the DAG is not enabled by default, it should be enabled for all
DAGs with two or more members that use continuous replication. DAC mode shouldn’t be
enabled for DAGs that use third-party replication mode unless specified by the third-party
vendor.
When the DAC property is set, split-brain conditions are avoided. Even though a server
is located in a site that has quorum, it will not mount its databases until it receives the okay
from a server that has already mounted its databases.
Consider the above scenario again, this time in a DAG that has DAC enabled. Power has
been lost to the primary datacenter, and the secondary datacenter has been activated for
service. Power is restored to the primary location though initially the WAN is not back online.
The Exchange Servers and the witness server all come back online and the site has quorum,
but as no Exchange Server in that site can contact any Exchange Server in the DAG that has
already mounted its databases, they do not mount their own databases. Service remains active in the secondary datacenter.
Later the WAN is restored and the Exchange Servers in the primary site can contact the
Exchange Servers in the secondary site. The cluster is updated with the latest configuration of
the cluster from the secondary site, and the servers in the primary site learn they were evicted
from the cluster. Therefore, the cluster service stops on these machines. At no time did
these primary datacenter servers communicate with a member of the DAG that had already
mounted its databases.
Once the primary datacenter servers are added back into the cluster and are members of
the DAG again, they will see that they are passive servers and that they can resume transaction log copying from the changes made in the secondary datacenter. With regards to being
able to mount their databases, they will be able to communicate with another member of the
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DAG (in the secondary datacenter) that has already mounted its databases, and so will receive
permission to mount its own copies of the databases if required to.
Finally, to fully restore service and move the active copy back to the primary site, the active
copy of the database is moved and successfully mounted without data loss, on to a server in
the primary site.
How DAC mode works
To avoid the split-brain condition, in Exchange Server 2013 a mailbox server will not mount its
databases until it has confirmation from another server in the DAG that it is allowed to mount
its databases. In a scenario where the entire site is down and then comes back online, each
Exchange Server will boot into a mode where it is not allowed to mount databases. All of the
servers in the primary site will communicate with each other, but as no server has the right
to mount databases they will all not mount their databases. Once the WAN is restored and
connectivity resumed to the secondary datacenter, the servers in the primary site can communicate with servers that have mounted databases, and so are allowed to mount their own
databases if required.
DAC mode is managed by the Active Manager, the process that mounts databases on
a server, storing a bit in memory that reads either 0 or 1. On booting, an Exchange Server
always has this bit set to 0. It will never mount databases whilst the value of the bit is 0, and
it will never change the value to 1 unless it can communicate with another server in the DAG
that already has the value set to 1.
This communication of the value of the DAC mode bit is known as the Datacenter Activation Coordination Protocol (DACP).
Enabling DAC mode
To enable a DAG with two or more nodes to utilize the DACP protocol, set the
DatacenterActivationMode property of the DAG to DagOnly.
# Enables DAC mode
Set-DatabaseAvailabilityGroup "DAGName" -DatacenterActivationMode DagOnly
To determine if a DAG is running in DAC mode use either of the following.
# A value of DagOnly means DAC mode is operational for the named DAG.
(Get-DatabaseAvailabilityGroup DAGName).DatacenterActivationMode
Get-DatabaseAvailabilityGroup DAGName | FL DatacenterActivationMode
If you use the Exchange 2013 Server Role Requirements Calculator (http://aka.ms/E2013Calc)
and use the scripts that you can export from the Distribution tab of this workbook, you are
given the option of enabling DAC mode as part of this export (see Figure 2-1). As long as you
have configured values such as server names and other DAG settings in the calculator, the
script export process will create a CSV file called DAGInfo.csv that will be used by the CreateDAG.ps1 script. When you are ready to create the DAG in your Exchange Server deployment,
and your disks are configured as required by the Diskpart.ps1 script (also from the calculator),
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then the CreateDAG.ps1 script will make the DAG and set the settings on it for you. These settings include the maximum mounted databases, witness shares, and server names.
FIGURE 2-1 The Export DAG List dialog box showing the DAC Mode drop-down list with DAGOnly se-
lected
Other scripts that can be exported from the calculator will create the databases and the
database replicas for you across all of the servers in the recommended distribution.
DAC mode for DAGs with two members
In a DAG with just two members you need to take into account special considerations when
enabling DAC mode because the DACP bit is not enough to protect against split-brain scenarios.
NOTE You cannot enable the DatabaseActivationMode setting on DAGs that have only a
single member (see Figure 2-2).
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FIGURE 2-2 Error displayed when attempting to set DACMode on a single member DAG
In a DAG with only two members and DAC mode enabled, the boot time of the witness
server (which would be in the same site) and the time that the DACP bit was set to 1 are compared. If the time that the DACP bit was set to 1 is earlier than the boot time of the witness
server, it is assumed that all of the servers in the site were rebooted, and thus an event has
occurred across the site to cause a site-wide outage.
If the DACP bit was set at a time later than the witness server’s boot time, it is assumed
that the DAG member had a reboot event that was not related to a site outage.
If the reboot event is not related to a site outage (in other words, the time the DACP bit
was set is later than the witness server boot time), the DAG member is allowed to mount
databases.
IMPORTANT REBOOT TIME AND CLUSTERS
The boot time of the witness server is used to help distinguish the type of reboot event
that has occurred, so you should never reboot the witness server and the sole DAG member at the same time. If they are rebooted at the same time, the sole DAG member will
not be allowed to mount databases. If this happens, you need to run the RestoreDatabaseAvailabilityGroup cmdlet to reset the DACP bit and permit the DAG member
to mount databases.
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Other benefits of DAC mode
As well as preventing split-brain condition in a DAG, the DAC mode setting allows the use of
Exchange Server cmdlets to perform datacenter switchovers. The cmdlets that can be used
include the following:
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■■
■■
■■
■■
Stop-DatabaseAvailabilityGroup This cmdlet is used to remove a member from
the DAG or to remove an entire site from a DAG; like when you need to switch service
over to the secondary datacenter. This cmdlet can be run only when the DAG is configured with a DatacenterActivationMode value of DagOnly. In the event of server or site
failure (rather than planned switchover), you must use the ConfigurationOnly switch to
update the state of the DAG members in the Active Directory when the actual servers
are unavailable.
Restore-DatabaseAvailabilityGroup This cmdlet brings the DAG online in a switchover event. You need to mention the site name (-ActiveDirectorySite) and optionally the alternative witness server and directory if these were not already configured
as part of the DAG. In the event of a site outage, this cmdlet would be used after a
failed site is removed from the DAG using Stop-DatabaseAvailabilityGroup. This cmdlet
forcibly evicts from the DAG those servers on the StoppedMailboxServers list and
thus resets the requirements for quorum. This allows the remaining DAG members to
establish quorum, mount databases, and provide service. If there is an even number
of surviving DAG members, or if there is only one surviving DAG member, then this
cmdlet configures the DAG to use the alternative file share witness. A file share witness
is required when the cluster has an even number of nodes (to provide a tie-breaking
3rd vote).
Start-DatabaseAvailabilityGroup This cmdlet is used to restore service in a recovered datacenter after the datacenter switchover to the secondary datacenter has
occurred, and now the recovered datacenter is ready to take part in providing service
again. After running this cmdlet, the servers that had been evicted from the cluster
by the Restore-DatabaseAvailabilityGroup cmdlet can be restored to service either by
bringing all of the servers in a DAG in a given site online, or by specifically mentioning
the server to bring online, should not all of the servers in the site be ready and available to resume service.
Move-ActiveMailboxDatabase This cmdlet is used to bring the active database
from one server to another. In the scenario of site recovery it would be used to move
the databases that are active in the secondary datacenter back to being active in the
primary datacenter. It is used to finish recovery of Exchange Server following the resumption of service in the restored primary datacenter.
Update-MailboxDatabaseCopy This cmdlet is used to resume replication between
the active and a selected passive copy after the service has been restored. Note that
this cmdlet can also be used to initially seed a new database copy and is not just used
when restoring service after an outage.
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Given customer node requirements, recommend quorum
options
Quorum is a feature of the cluster service in Windows Server. The cluster service is used to
provide the server-up/server-down management of the Exchange Database Availability
Group (DAG). At a simple level of description, the cluster nodes all communicate with each
other and share a configuration that they all store, called the quorum database. One cluster
member is deemed the owner of this database in the case of conflicting information in the
copies of the quorum database.
Exchange Server uses a configuration of the cluster service known as Node and File Share
Majority. In this configuration the quorum database is stored on all servers and replicated
from the server with the writable copy of the quorum to all of the other servers in the cluster.
The cluster can remain up and running and providing service if a majority of nodes of the
cluster are available. The majority is calculated by taking the number of nodes in the cluster,
halving this number, and adding 1 to the result. Because a DAG can have up to 16 nodes, the
number of nodes in the cluster determines how many nodes need to be running for the cluster to be available for service. In the case of Exchange Server, if the cluster has majority it can
mount databases and service requests to the data in the mailboxes from the other services
within Exchange (such as transport and client access).
Table 2-1 shows you how many nodes need to be up in a cluster based upon the total
number of nodes in the cluster. If this or more nodes are online, it is said that the cluster has
majority, or it can also be said that the cluster has quorum.
TABLE 2-1 Number of nodes that need to be up to have majority
Nodes in
cluster
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NEEDED FOR
MAJORITY
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
You can see from Table 2-1 that as you increase your node count, the number of servers
that you need to keep online does not increase to the same pattern. Thus if you had a DAG
with three servers in it and added a fourth, you would not have increased your resilience
because you could still only sustain a single node failure
The file share witness
To avoid this issue of even numbers of nodes having the same resiliency as one less server in
the cluster, Exchange Server changes the quorum type depending upon the number of nodes.
When you have an even number of nodes in the cluster, the cluster is running Node and File
Share Majority, and when you have an odd number of nodes in the cluster, the quorum type
is Node Majority.
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You can see the type of quorum your DAG is running by using Get-Cluster DAGName
| Get-ClusterQuorum | Format-List in PowerShell, as shown in Figure 2-3. The same figure
shows the output of Get-DatabaseAvailabilityGroup E15-DAG-RED | Format-List Servers,
which shows that the DAG has three nodes in it and therefore the cluster reports that it’s
QuorumType is NodeMajority.
FIGURE 2-3 PowerShell output showing DAG and cluster properties
When you have an even number of Exchange Servers in the DAG, Exchange Server
changes the QuorumType to NodeAndFileShareMajority, and an additional server that hosts
a file share votes on the majority of the cluster. Note that the role of the file share in terms of
voting only comes into play when there is not enough servers online in the cluster to provide
majority on their own. Thus if you had a four node DAG and all four nodes where online,
though you would be in a Node and File Share Majority cluster, you would not need the vote
of the file share to see if you have quorum. If two of the servers in this four node DAG were
offline or unavailable (the other side of a disconnected WAN for example), the vote of the file
share witness server would come into play.
The file share witness is any Windows Server computer that can host a file share that is in
the same forest as the DAG, though the recommendation is a server running the CAS role
because all of the correct permissions are already in place for Exchange to create the folder,
share, access, and lock a file inside the share when it needs to.
The file share witness (and an alternative file share witness in another site for when you
have site failover) are set when you create the Database Availability Group. For example, the
following cmdlets create a DAG called DAG1 with both the file share witness and alternative
file share witness set.
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// Creating a Database Availability Group and specifying all of the witness servers
New-DatabaseAvailabilityGroup DAG1 -WitnessServer FS1 -WitnessDirectory C:\DAG\DAG1
Set-DatabaseAvailabilityGroup DAG1 -AlternateWitnessServer DRFS1
-DatacenterActivationMode DagOnly
The WitnessServer and WitnessDirectory parameters are valid in the New-DatabaseAvailabilityGroup cmdlet and in the Set-DatabaseAvailabilityGroup cmdlet. The AlternateWitnessServer parameter can only be set in the Set-DatabaseAvailabilityGroup cmdlet.
You are not required to pick a witness server, and if you do not, a CAS server in the same
site that you are running the New-DatabaseAvailabilityGroup cmdlet in will be selected. This
CAS server, if it coexists with a mailbox role server, cannot be a member of the DAG. If you
have an Exchange Server design that leads to a single DAG and co-located server roles, you
need to pick your own file share that is not one of the Exchange Servers in your deployment.
Exchange Server will not auto-select an alternative witness server.
NOTE CHOICE OF FILE SHARE WITNESS SERVER
Microsoft recommends that you use a client access server running on Microsoft Exchange
Server 2013 in the Active Directory site containing the DAG, but not a member of the DAG.
This allows the witness server and directory to remain under the control of an Exchange
administrator.
If you need to pick a file server that is not an Exchange Server, you need to add the Exchange Trusted Subsystem (ETS) universal security group into the local administrators group
of that server. If the file server is also a domain controller, you need to add the Exchange
Trusted Subsystem universal security group into the BUILTIN\Administrators group on any
domain controller in the domain, and wait for replication to complete. The Exchange Trusted
Subsystem group can be found in the Microsoft Exchange Security Groups OU in the root
domain of the forest.
Once the file server is selected from an available CAS, or you specify the server during the
creation of the DAG,1 or when you change the DAG settings, Exchange Server creates the directory specified or uses the default directory path and shares this folder. Multiple DAGs can
use the same witness server, but they must use a different path for the witness directory.
The file share witness is used when the cluster needs to determine if it has quorum and
there are not enough nodes online to achieve this. The cluster name owner, or the Primary
Active Manager (PAM) in the DAG, will attempt to lock a file on the file share witness. If they
are able to, this counts as an additional vote, and so in the case of an even number of servers
in the DAG, when half the servers are online the locking of the file share witness means the
site that contains the PAM will have an additional vote. Typically this means that they will
achieve majority.
Figure 2-4 shows a four node DAG across two sites. The file share witness is located in the
primary site, and all four servers are up and have mounted databases.
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FIGURE 2-4 Four node DAG with all servers online
In Figure 2-5, the file share witness vote means that one side of the cluster can reach
majority and mount databases. The other side of the DAG in the secondary datacenter cannot
reach majority, and so the cluster service stops and the databases dismount.
FIGURE 2-5 Four node DAG after a WAN outage
Cluster features in the operating system
Exchange Server 2013 can run on Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2. For the two 2012 versions of Windows Server, the Standard Edition is
sufficient as this contains the failover clustering feature. For Windows Server 2008 R2, a DAG
requires Enterprise Edition because the Standard Edition does not contain the failover clustering role.
EXAM TIP
Exchange Server 2013 SP1 or later is required when using Windows Server 2012 R2 as the
operating system.
In Windows Server 2012, support has been added for dynamic quorum and dynamic witness. In Windows Server 2012 R2, these features are enabled by default.
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Dynamic quorum is a feature where the node count for determining majority is not fixed
to the number of nodes in the cluster, but the number of nodes that were online at the point
of calculating quorum. In Windows Server 2008 R2, the number of nodes that are part of the
quorum calculation are as described in the previous section, which means that the number
of nodes for quorum equals the number of servers in the cluster. In Windows Server 2012, a
cluster node loses its vote if it goes offline and regains it when it comes online. Therefore, a
DAG with three nodes on Windows 2008 R2 has to have two nodes up to keep majority. The
file share witness is not used because there is an odd number of nodes. But the same DAG
running on Windows Server 2012 or 2012 R2 can sustain the loss of two nodes one after the
other and keep majority. It does this via dynamic quorum. The loss of one server majority
is recalculated and the DAG becomes a two node DAG with file share witness. That is three
votes, and as long as either two nodes, or the witness server and the single DAG node are
up, Exchange can keep mounting databases. Simply put, if the cluster experiences a failure
that allows it to remain up and maintain quorum, then dynamic quorum can recalculate the
quorum. This allows the cluster to survive additional failures and maintain quorum (more than
it could without dynamic quorum). However, if your initial failure is widespread enough to
cause quorum loss, the cluster will go down. So dynamic quorum really helps when you have
cascading failures.
Dynamic quorum does not help in a scenario where you would lose quorum. For example,
in a single site DAG with three nodes and you lose two nodes at the same time, you go from
three votes (no file share witness) to one vote. One vote is not enough to maintain quorum.
This allows for a scenario called last man standing where you can progressively loose
nodes and thus votes until you have one server remaining. Note that this one server might
not host all of the databases or be sized to host the load of all the user connections, and so
even though the cluster is up and one Exchange Server is up, not all of your databases might
be up.
IMPORTANT CONSIDERING DYNAMIC QUORUM
Do not design your DAG to take into account dynamic quorum. That means do not design
every server in the DAG to hold a replica of every database, and size each server to support
all of the users in the event of last man standing.
If you have two nodes left, dynamic quorum removes the vote from one node. One node
will have a vote and one node will not. Use Get-ClusterNode ClusterName | Format-Table
Name, DynamicWeight, State to determine which node has the vote, and do not shut that
node down. If you do, the other node’s cluster service will go offline as it does not have a
vote. The cmdlet will report DynamicWeight = 1 for the server that has the vote.
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Quorum scenarios
Now that you have an understanding of the different scenarios where a file share witness will
come into play, and that having quorum (or majority) is vital to maintaining service, we will
look at some customer scenarios and best choices.
We will look at the following four scenarios:
■■
■■
■■
■■
Coho Winery has two servers at their vineyard and no other locations to host offsite
servers.
Blue Yonder Airlines has a six node DAG with two of the servers in a secondary datacenter for high availability and site resiliency purposes.
Northwind Electric Cars has a well-connected office and factory located in different
cities with users at both locations.
Humongous Insurance has 32,000 employees and need to have automatic failover to
the secondary datacenter in the event of an outage in their primary New York datacenter.
Coho Winery single site two node This customer only has a single site but needs to
ensure their email server is always available because they use it to receive orders from their
suppliers. Therefore, they have a two node DAG. Their file share witness is located on their
file server. They are running Windows Server 2012 R2 as their operating system for Exchange
Server and so dynamic quorum comes into the equation when they need to shut down a
server for maintenance, and they need to ensure they move the voting node and then keep
that server online.
Blue Yonder Airlines This is a midsized regional airline company that has centralized all
of its email in its head office in London. They have a disaster recovery datacenter near Oxford.
They have a six node DAG supporting 4000 mailboxes with two of the nodes in the disaster
recovery datacenter. All active mailbox databases are replicated to two other servers, one at
the HQ for initial failover, and one at the DR site for second failover. They can lose one server
and all of the mailbox databases remain on servers in the head office. At the loss of a second
server in London, most mailboxes are activated on the two remaining servers in London but
a small handful are activated in the secondary datacenter. The loss of two servers in London
is acceptable because cross-site failover of mailbox databases is allowed. However, because
they are running Exchange Server 2013 on Windows Server 2008 R2 they cannot use dynamic
quorum. Therefore, because the cluster is a six-node cluster, it will make use of the file share
witness. This means that with the loss of two servers in the primary site majority is maintained, or the loss of one server in the event that the WAN should also fail.
When two servers fail, but the WAN is online, there are four reachable servers. Four is
a majority of six. When three servers fail, the file share witness vote becomes important
because there are now three servers online (which is not a majority of six), but the extra vote
from the file share witness means there are four votes. These votes are a majority, and so the
cluster remains running. As long as the three failed servers are not the only servers a given
database was replicated to, all mail databases remain online. If the WAN to the DR site goes
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offline, the two servers near Oxford will go offline (because they do not have majority). IT
pros in the primary site must ensure that three Exchange Servers and the file share witness
remain online while the WAN is offline.
FIGURE 2-6 Exchange 2013 Storage Calculator used to model WAN and server failure scenarios
Exchange Server Role Calculator for Exchange 2013 is a great tool for modeling these
scenarios. For example, in Figure 2-6, you can see this six-server node with the WAN failed
between sites (the WAN buttons reads, “Recover WAN”), and thus the two servers in the secondary datacenter are offline, and one server in the primary site has also failed. Even though
Blue Yonder Airlines has lost the resources of half of their Exchange Servers, they are still able
to maintain quorum and service email to their employees.
Northwind Electric Cars This customer has 2,000 staff, with 1,500 in the main office and
500 on the assembly line. There is good WAN connectivity between the sites even though
they are located in different cities. Therefore they opted for two DAGs and a file share witness
server located in each site (one for each DAG). The user mailboxes are located in the DAG
that is in the majority at the local site. Quorum is maintained per DAG, and so each office is a
separate failure domain.
If the WAN fails, the Exchange Servers that are in the secondary site for each DAG go offline. This results in some Exchange Servers in each location going offline, but because these
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servers are just passive copies and not used for transport shadow redundancy from the other
servers in the site, there is no immediate impact to the users.
When a site fails, the mailboxes for that site could be activated in the other site if recovery
of the primary site would exceed any required SLA. The other site and its servers would not
be affected by the outage in the first site.
Humongous Insurance This customer is planning a migration to Exchange Server 2013
from Exchange Server 2007. As part of the migration, Humongous Insurance will make use of
new technologies such as 8 TB SATA drives to reduce their storage costs in a JBOD deployment that is an eight node DAG across two datacenters. They will locate their file share witness in a third datacenter that has MPLS networking links to both the primary and secondary
datacenters. Figure 2-7 shows the Distribution tab of the Exchange Server 2013 storage calculator with four servers in each site, and the file share witness in a third datacenter. The WAN
in the primary datacenter has failed. The MPLS links that they have in place from the various
user locations remain working, as does the link to the file share witness site and the secondary
site. On the WAN failing, the secondary site can reach the file share witness and therefore is
able to have five votes from a DAG of eight nodes. It is therefore able to keep majority even
though the primary servers are all unreachable. The Exchange mailbox databases all mount
in the secondary site automatically, and because the primary site is not able to reach the file
share witness, it is only able to acquire four votes. Therefore, the cluster service in the primary
datacenter does not get majority, and the databases dismount.
FIGURE 2-7 Modeling a WAN failure and automatic failover with a third site file share witness
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Planning cross-site DAG configuration and configuring
DAG networks
When you have a DAG that crosses a WAN boundary, there are a number of additional items
to consider in your configuration. These are:
■■
The number of DAGs you need
■■
DAG IP addressing considerations
■■
Configuring DAG networks and rediscovering DAG networks
■■
Network compression
How many Database Availability Groups do you need?
There are a number of aspects to the question regarding the number of DAGs that you need.
The most important aspect to consider is the location of your user population.
If you take a simple Exchange Server scenario like the one shown in Figure 2-8, you will see
that there are users in a number of network locations. You will also see that their nearest network is Paris or Berlin, depending on their location. There are also users at each main office in
Paris and Berlin. The servers are kept at the main office.
In the scenario in Figure 2-8, there are users located in both Paris and Berlin. Each user
connects to their mailbox which is located in the main office. If the four Exchange Servers in
the scenario were placed into a single DAG, an outage of the Paris-Berlin WAN would result
in all of the mailboxes being mounted in Paris because that is the location of the file share
witness. This would result in a loss of access to their mailboxes for the users in Berlin, and the
sites connected to it.
FIGURE 2-8 Exchange Server deployment in multiple offices with branch offices
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If the network topology for this company is such that direct connections from, for example
Rostock, reached Paris by way of Berlin, then when the Paris-Berlin WAN goes offline Rostock cannot reach Paris. Even though their mailbox is online, they cannot access it from the
office. Therefore, this scenario needs two DAGs. A Paris DAG with one or two servers in Paris
depending upon load, sizing, and availability requirements, with a site-resilient copy in Berlin.
This DAG would have a file share witness in Paris and a Berlin-homed DAG with the file share
witness in Berlin. When the WAN fails, the Paris DAG will mount its databases in Paris, and
the Berlin DAG will mount its databases in Berlin. This is known as an Active/Active (Multiple
DAG) model and can be seen in Figure 2-9. This model avoids the WAN link between the
two sites being a potential single point of failure, though it does require more servers than a
single DAG for the same user count and mailbox size. If the WAN can be a resilient WAN, an
Active/Active (Single DAG) model can be deployed where there are active mailbox databases
mounted in each site. Because the WAN is resilient, an outage of part of the WAN results in
an alternative route being used, and the mailbox databases staying online in their desired
locations.
FIGURE 2-9 A two datacenter design where users are located at or networked to each datacenter
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DAG IP addressing considerations
In a Windows Server 2008 R2 or Windows Server 2012 cluster, you need to have an IP address
assigned to the DAG for each site that the DAG can operate in. You can either assign an IP
address manually when creating the DAG in Exchange Management Shell, or allow DHCP to
assign an IP address to the DAG. For auto assignment of IP addresses, you obviously need to
have a DHCP server running in each site that the DAG is in, and available IP addresses at the
time of failover. If you do not have a DHCP server or servers that can supply IP addresses to
each site, or you cannot guarantee available IP addresses in the DHCP pool when failover occurs, you should manually assign a valid IP address for each site and ensure that nothing else
uses that address by removing it from the DHCP pool or updating your documentation on
available addresses.
In a Windows Server 2012 R2 cluster with Exchange Server 2013 SP1 or later, you can create a DAG that does not have an underlying cluster name or IP address requirement. This is
known as a DAG without a cluster administrative access point. DAGs without administrative
access points have the following features:
■■
■■
■■
■■
■■
■■
There is no IP address assigned to the cluster/DAG, and therefore no IP address resource in the cluster core resource group.
There is no network name assigned to the cluster, and therefore no network name
resource in the cluster core resource group
The name of the cluster/DAG is not registered in DNS, and it is not resolvable on the
network.
It is not required to pre-create the cluster name object (CNO) in the Active Directory.
The cluster cannot be managed using the Failover Cluster Management tool. It must be
managed using Windows PowerShell, and the PowerShell cmdlets must be run against
individual cluster members.
There is no computer object that needs to be created in the Active Directory for the
cluster. This avoids a series of administrative tasks and removes potential issues if the
object is accidently deleted.
Each of these features will impact the way you interact with the cluster, most notably in
terms of the management tools used. But the features that remove the need for a network
name (CNO) and IP address reduce the resources required by the cluster service, and therefore reduce the items that if they fail will cause the cluster to failover or go offline.
To create a DAG without an administrative access point, use the following in the Exchange
Management Shell.
New-DatabaseAvailabilityGroup -Name DAG1 -WitnessServer EX4
-DatabaseAvailabilityGroupIPAddresses ([System.Net.IPAddress])::None
IMPORTANT BACKUP SOFTWARE CONSIDERATIONS
Some third-party backup software that connects to the cluster using the DAG name will
not work with a DAG that has been created without an administrative access point.
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Configuring DAG networks and rediscovering DAG networks
The cluster that underlies the DAG requires at least one network that all the nodes share and
that the clients of the DAG can use to reach the mailbox databases. Optionally you can have
a second network in the cluster that Exchange will use for transaction log replication. Clients
do not connect to the DAG via the replication network and so it is dedicated to the role of
replicating transaction logs as fast as the network will allow.
It is important to consider if you need a replication network at all. In a cross-site DAG,
the most likely configuration for the WAN between the sites is that you have a single WAN.
Therefore, all cross-site communication is on this single connection even though you have
two network cards in each server. Splitting the client and replication traffic onto separate networks in the LAN at each end, only to combine them on the WAN, means that in reality you
have a single network that the replication traffic will cross.
If you do have two WAN links, a large enough user population, or dedicated network
switching and trunking such that you really can take the replication traffic off of the network
that the clients are on, then it is worth doing. For smaller networks or networks with capacity
beyond their requirements and sufficient switching capacity, it is probably easier to keep the
administration of Exchange Server simple, and keep to a single client and replication network.
If you have a second network for replication, it must be configured correctly. For Exchange
Server this network should be configured as follows:
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Not registered in DNS It is not reachable by clients, and so clients should not resolve this server on this network. This setting can be seen in Figure 2-10.
FIGURE 2-10 DNS settings for the replication network
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■■
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Not having a default gateway You should have one default gateway on the server
and this should be on the network card that all unknown routes use (the client network
in our example). The replication network should have manual routes configured so that
you can reach the replication network in the other sites.
The client or MAPI network is listed above the replication network in the
network binding order The binding order can be changed from the Network
Connections window. Press ALT to see the menu and then choose Advanced, and
Advanced Settings. The Advanced Settings dialog box is shown in Figure 2-11. Note
that Microsoft recommends that IPv6 is not disabled (see http://support.microsoft.com/
kb/929852).
FIGURE 2-11 Setting the network binding correctly for a dedicated replication network
If you get the network card and client/replication network configuration correct, Exchange
Server 2013 will auto-configure your DAG networks for you. The DAG networks are a configuration that helps Exchange understand how the network is configured. They are not physical
networks or settings on the network card.
If your Exchange Servers have networks other than those that will be used for clients and
replication, you will need to disable them in the DAG network. Examples include management
networks and backup networks. If you have these additional networks you have to manually
configure your DAG networks and then use the -ignorenetwork $true parameter in Exchange
Management Shell to mark the network as not to be used by the DAG.
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Network compression
When a DAG is created, Exchange Server will by default compress network traffic between the
nodes when they go cross-site, but by default network traffic is not compressed within the
site. Compression takes a little additional CPU to complete at each end, but reduces the traffic
considerably. In places where you have limited bandwidth the extra CPU impact is acceptable
as you usually have capacity, whereas you might not have capacity on the WAN.
There is typically not much point enabling compression on a LAN as the capacity is available for uncompressed traffic.
Compression is set as a property of the DAG and not the underlying DAG network. To
check the compression of your DAG, use the following Exchange Management Shell cmdlet.
Get-DatabaseAvailabilityGroup E15-DAG-RED | Format-List NetworkCompression
The possible values for network compression are:
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Disabled All intra-DAG traffic is not compressed regardless of DAG node location.
Enabled All intra-DAG traffic, including replication and database seeding is compressed.
InterSubnetOnly All DAG replication traffic (not seeding traffic) is replicated between subnets. Replication within the LAN is not compressed.
SeedOnly Only database seeding traffic is compressed.
Compression generates a saving of about 30 percent over uncompressed traffic and
should be used inter-subnet unless you have WAN optimizers that can do a better job. Given
that all of the traffic is typically unique, WAN optimizers are unlikely to achieve this and
should be turned off for traffic on the replication port of TCP 64327.
NOTE CHANGING THE TCP PORT
The replication port of TCP 64327 can be changed. If it is, firewalls on the Exchange Server
need to be updated to allow the new port and network inspection devices should be configured to ignore the traffic on this new port.
Creating a DAG on Windows Server 2012 and 2012 R2 Servers
A cluster name object (CNO) is automatically created in the Active Directory by cluster service
on Windows Server 2008 R2 when the DAG is created. This does not happen automatically on
Windows Server 2012 or 2012 R2 and needs to be created manually. If you are making a DAG
without an administrative access point, you do not need to pre-create a CNO because this
type of DAG does not need one.
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MORE INFO PRE-STAGING THE CLUSTER NAME OBJECT
For instructions on pre-staging the cluster name object see http://technet.microsoft.com/
en-gb/library/ff367878(v=exchg.150).aspx. There are scripts available online to do this for
you as well, such as this one http://eightwone.com/2012/12/20/cluster-name-objectpre-staging/ by Exchange Server MVP Michel de Rooij.
Thought experiment Patching Exchange Servers
In this thought experiment, apply what you’ve learned about this objective. You can
find answers to these questions in the “Answers” section at the end of this chapter.
1. You are the network administrator of Fabrikam Inc and you have six Exchange
2013 SP1 servers distributed across two sites. Your operating system is Windows
Server 2012 R2. There are four servers in your primary site and two servers in
the disaster recovery site. DAG Mode is set to DAGOnly. Your file share witness is
located in the primary site. Each database has four copies and is therefore replicated three times from the active copy. This replication is twice in the primary
site and once more to the DR site.
2. How many servers can you switch off at a given time and ensure quorum is
maintained and service stays online for users? Cross-site failover of databases is
allowed.
3. In the event of a WAN outage, what does the maximum number of servers that
you can patch at a single time reduce to?
Objective summary
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Datacenter Activation Coordination (or the DatacenterActivationMode parameter) is
recommended when you have more than two servers in the DAG.
Ensure that you understand that two servers in a DAG should still have Datacenter
Activation Coordination enabled, but be aware of the implications of restarting the file
share witness at the same time as restarting a DAG member.
DAC mode allows you to use the Exchange cmdlets only to switch or failover to a secondary datacenter and to switch back again upon resumption of service without the
risk of split-brain condition occurring in the cluster.
Quorum is both the database in the cluster that stores the cluster settings (it is the
cluster hive in the registry), and a term that indicates that the cluster has majority.
Exchange Server manages the cluster type, changing it from NodeMajority to NodeAndFileShareMajority depending upon the number of servers in the cluster. NodeAndFileShareMajority is used when the cluster has an even number of nodes.
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The file share witness is used to provide an extra vote to determine quorum in the
event that only half of the nodes are reachable in an even numbered cluster. The file
share witness contains a file called Witness.log that one Exchange Server, the Primary
Active Manager (PAM), which is the server that owns the cluster resources, attempts to
lock to ensure majority. Therefore, ensure that the PAM and the file share witness are
both located in the primary site unless the witness server is in a third site.
It is recommended to keep your Exchange Server deployment simple as that reduces
the risk of human error from causing a site or server outage. Therefore a single network for DAG replication and client traffic is recommended.
Objective review
Answer the following questions to test your knowledge of the information in this objective.
You can find the answers to these questions and explanations of why each answer choice is
correct or incorrect in the “Answers” section at the end of this chapter.
1. One winter’s day a supplier-level power failure occurs impacting the primary site. Staff
are sent home and your requirement is to bring Exchange Server online in the disaster
recovery site. What are the steps to do this when the file share witness is located in the
primary site and DatacenterActivationMode is set to DAGOnly? The alternative witness
server had been configured when the DAG was originally set up.
A. Stop-DatabaseAvailabilityGroup -ActiveDirectorySite <PrimarySite> followed by
Resume-DatabaseAvailabilityGroup -ActiveDirectorySite <SecondarySite>
B. Stop-DatabaseAvailabilityGroup -ActiveDirectorySite <PrimarySite> followed by
Start-DatabaseAvailabilityGroup -ActiveDirectorySite <SecondarySite>
-WitnessServer FS1
C. Stop-DatabaseAvailabilityGroup -ActiveDirectorySite <PrimarySite> followed by
Restore-DatabaseAvailabilityGroup -ActiveDirectorySite <SecondarySite>
D. Stop-DatabaseAvailabilityGroup -ActiveDirectorySite <PrimarySite> followed by
Restore-DatabaseAvailabilityGroup -ActiveDirectorySite <SecondarySite>
-WitnessServer FS1
2. You need to design a DAG layout for a company with 5000 staff located around
the world. The company has three datacenters, one located in San Francisco, one in
Madrid, and one in Tokyo. Mailbox sizes mean that one server in each site is sufficient
to store the data and a second server is needed for high availability. The network infrastructure of the company allows all users to access all parts of the network via an MPLS
cloud network, but the fastest links are to the geographically closest datacenter. If the
MPLS network links fail, cross-site connectivity will be broken. What will this Database
Availability Group (or groups) configuration look like to ensure a working solution in
both active and failure scenarios?
A. Create a single DAG with two servers in each datacenter as members of this DAG
with the file share witness in Madrid.
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B. Create two DAGs, one with the PAM and file share witness in San Francisco and
the other with the PAM and FSW in Tokyo. Add one server in Madrid to the San
Francisco DAG, and the other server to the Tokyo DAG.
C. Create three DAGs, one for each datacenter and expand the DAG to the nearest
other datacenter where an additional server will be placed for site resilience for
that primary datacenter of the DAG.
D. Create four DAGs. One in each datacenter with two servers in it, and then a fourth
DAG that holds the replica servers and is distributed geographically across all of
the datacenters.
Objective 2.2: Design, deploy, and manage a siteresilient CAS solution
As well as ensuring that your databases are resilient across different mailbox servers, it is also
important to ensure that the client access layer is redundantly available as well. Clients all
connect to their mailbox layer via the client access server (CAS) layer. Unlike earlier versions of
Exchange Server, there is no client connectivity direct to the mailbox database.
This objective covers how to:
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Plan site-resilient namespaces
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Configure site-resilient namespace URLs
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Perform steps for site rollover
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Plan certificate requirements for site failovers
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Predict client behavior during a rollover
Planning site-resilient namespaces
In Exchange Server 2010, failover to a second site of the client access layer involved a change
in the namespace. The namespace is what users and clients need to connect to Exchange to
reach their mailboxes. For example, mail.contoso.com would be a namespace for the Contoso
Pharmaceuticals email service and dr-mail.contoso.com might be a namespace needed
when mailboxes are moved to the DR site. If you used protocol specific namespaces such as
smtp.contoso.com for transport and owa.contoso.com then you would need disaster recovery/second datacenter versions of the primary URLs as well.
In the event of a full site failover, it is possible to update DNS and move the entire
namespace to the secondary site. But while some databases are on the primary site and others on the secondary site, and the client access layer is operational at both sites. This meant
that in Exchange 2010 you needed two namespaces. The primary driver for this was that con-
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nectivity between the CAS layer and the mailbox databases was RPC based which required a
fast network with low latency between the tiers and so performance issues could occur if the
CAS tier was in a separate site from the mailbox database. That is, your mailbox was on a database in the secondary datacenter but you were using a CAS server at the primary datacenter. In Exchange 2010, cross-site access could be disabled and then CAS connectivity would
failover to the remote site, but a namespace change would occur.
In Exchange 2013, all connectivity between Exchange Servers has been moved to the HTTP
protocol (and SMTP for transport, and IMAP or POP3 if using an older client). There is no
cross-server RPC connectivity. This means that the client connection is ultimately made to the
server that contains the active mailbox database for that user’s mailbox and that all connectivity happens to and from that server. Exchange Server 2013 provides a proxy layer, known as
the CAS role. This proxy layer ensures that user connections are made to the correct mailbox
server. Therefore a user or client can connect to any CAS role server, authenticate to prove
who they are, and then the CAS role proxies their connections to the mailbox role server that
holds their active mailbox database. This is shown in Figure 2-12.
FIGURE 2-12 CAS proxy to active mailbox database
In Figure 2-12, it does not matter if the user connects to either of the two CAS servers
shown because both of them will proxy the user to the same mailbox server, the one that is
active for their mailbox.
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REAL WORLD MULTIPLE CAS ROLES AND MAILBOX ROLES
Though Figures 2-12 and 2-13 show the CAS role and the mailbox role as installed on separate servers, this is for the purpose of illustration only. Microsoft recommends that you use
multi-role installations.
Consider Figure 2-12 in real life. This would require five Exchange Server and Windows
Server licenses as well as the hardware or virtual resources to run this configuration. If
the company requires three mailbox servers, installing CAS and mailbox on three servers
reduces the license count, reduces the hardware or virtual resources, reduces the servers to
manage, and increases the high availability of the CAS role from two servers to three, all at
a cost saving both for deployment and ongoing running costs.
When Exchange Server 2013 is installed into more than one datacenter, and some or all of
these datacenters have an inbound Internet connection, it is possible to use different technologies to direct the user at a specific datacenter. For example, this could be a technology
that routes the user’s connection to their geographically closest datacenter rather than the
datacenter that holds their active mailbox.
The Exchange CAS layer will then direct the traffic using the same protocol that the user
connected with, and which is a protocol that is capable of dealing with lower latency links, i.e.
HTTP, to the mailbox server that is active for that user’s mailbox.
This can be seen in Figure 2-13, which is an expansion of the network shown in Figure
2-12. If in this figure the user has a mailbox in Ireland but was travelling in the United States
(US), they would be directed to the San Antonio datacenter as that is closer to them over the
Internet. When on the private network of the company, the endpoint the user has connected
to in San Antonio is then connected to the location of the mailbox server in Dublin. The user
receives fast Internet connectivity rather than a high latency connection to another part of
the world over the public Internet, and the performance they see from Exchange Server is
quick. This is similar to the model that Office 365 uses with the Exchange Online service, and
importantly for namespace simplicity, allows the user to use a single namespace regardless
of their location or the location of their mailbox. In this example, if this was Contoso, all users
throughout the world would use mail.contoso.com to access Exchange Server.
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FIGURE 2-13 Single namespace design with multiple datacenters
MORE INFO USING THE LAB ENVIRONMENT
MVP Paul Cunningham has written a blog post at http://exchangeserverpro.com/exchange2013-client-access-server-high-availability/ which shows how to configure the Outlook
Anywhere namespace for high availability and quick failover times in a lab environment
using DNS round robin.
This is an excellent scenario to test in a lab as it introduces you to the concepts of load
balancing without the layout of a load balancer, though for real world experience we
recommend downloading a trial virtual load balancer from one of the vendors listed at
http://technet.microsoft.com/en-us/office/dn756394.
In past examples, we have used both bound and unbound namespace models. A bound
namespace is where the name is specifically targeted to a single datacenter and an unbound
model is where the namespace works regardless of which datacenter you connect to.
Configuring site-resilient namespace URLs
Once you have decided upon the type of namespace that you will have with Exchange Server
2013, and the domain name that you will use for the namespace, you need to configure the
InternalURL and ExternalURL of a series of web services and the hostname value for Outlook
Anywhere. These URLs and hostnames will direct clients to the correct servers by the client
resolving that server via DNS.
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The majority of clients obtain their settings via the AutoDiscover service. This service returns to the client the InternalURL and ExternalURL for each web service, and the hostnames
for Outlook Anywhere based on the site that the user’s mailbox is active in. The Autodiscover namespace is the first namespace value that you need for Exchange. The Autodiscover
namespace is always the SMTP domain name (such as contoso.com) or Autodiscover and then
the SMTP domain name (for example autodiscover.contoso.com). This namespace is unbound,
that means it is the same regardless of where users are located. It only changes where you
have more than one SMTP namespace (for example contoso.com and contoso.co.uk), and then
Autodiscover is based upon the user’s SMTP domain in their email address.
If you want your users to connect through a single namespace, such as mail.contoso.com
for all Internet facing sites as described above, then every web service in Exchange Server will
have the same URL regardless of site. If you take a look at the example in Figure 2-14, you
can see that though there are three sites, two of which are accessible via the Internet, the URL
used for each service in each site will be mail.contoso.com.
FIGURE 2-14 Setting URLs based on namespace design
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For the URLs in a single namespace model, as shown in Figure 2-14, it does not matter if an
ExternalURL is set for each service in Oslo, as the namespace is the same in all sites. If Figure
2-14 represented a company with multiple namespaces, the following could be an example
that would be needed for the ExternalURLs
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Dublin: ie-mail.contoso.com
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San Antonio: us-mail.contoso.com
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Oslo: No external namespace
In the event of a failover, the single namespace model would require no additional configuration as a device such as a geo load-balancer or IP AnyCast would direct traffic to any
working datacenter. The working datacenter is either capable of hosting mailbox databases
from the DAG that was active in the failed datacenter, or being able to reach the datacenter
that is hosting the databases.
In the event of a failure with a bound namespace model, where different URLs are bound
to servers per datacenter, things work differently. If have an outage in Dublin (based on Figure 2-14), and ie-mail.contoso.com namespace becomes unreachable, you will need to either
wait for the outage to resolve itself. Alternatively you could manually update DNS to point
ie-mail.contoso.com to the same IP address as us-mail.contoso.com. Connections will now
either connect back to Dublin over the WAN (if it is still up and it was an Internet connection
outage only), or you will need to failover the databases to the DAG’s secondary datacenter in
San Antonio. Of course technology like DNS-based geo-load balancing can be used to swap
the DNS records to the working datacenter for you rather than doing it manually.
Setting the namespace URLs in Exchange Server
The steps to configure the site resilient namespace are to set the ExternalURL for the following services using either ECP or Exchange Management Shell:
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Outlook Web App https://mail.contoso.com/owa
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Exchange Control Panel https://mail.contoso.com/ecp
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Outlook Address Book https://mail.contoso.com/OAB
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ActiveSync https://mail.contoso.com/Microsoft-Server-ActiveSync
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Exchange Web Services https://mail.contoso.com/ews/exchange.asmx
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Outlook Anywhere mail.contoso.com (note that this is the ExternalHostname property and not ExternalURL)
In sites that are not Internet connected, such as Oslo in Figure 2-14, you need to leave the
ExternalURL blank (or set it to $null). The InternalURL is often set the same as the ExternalURL
because that makes connectivity for users easier to manage, regardless of where the user is, if
the URL is the same. If the InternalURL is different it should be set the same for every server in
the site.
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EXAM TIP
By default the InternalURL is the server’s FQDN and the ExternalURL is null. For Outlook
Anywhere the InternalHostname is the server’s FQDN and the ExternalHostname is null.
All of the servers in a site should have the same value for the URLs and hostname for a
given protocol or service.
An example of setting the Outlook Web App URL for the multi-namespace example in
Figure 2-14 is as follows.
Set-OwaVirtualDirectory <ServerNameInDublin> -InternalUrl https://ie-mail.contoso.com/
owa -ExternalUrl https://ie-mail.contoso.com/owa
Set-OwaVirtualDirectory <ServerNameInSanAntonio> -InternalUrl https://us-mail.contoso.
com/owa -ExternalUrl https://us-mail.contoso.com/owa
Set-OwaVirtualDirectory <ServerNameInOslo> -InternalUrl https://mail.contoso.no/owa
-ExternalUrl $null
NOTE PROTOCOL SPECIFIC LOAD BALANCING
With a layer 7 load balancer in front of Exchange Server, it is possible to use protocol
specific URLs. When a protocol fails, the load balancer will automatically connect you to
a different server for just that protocol. You can find out more how URLs such as https://
owa.contoso.com/owa and https://phone.contoso.com/microsoft-server-activesync can
work at http://blogs.technet.com/b/exchange/archive/2014/03/05/load-balancing-inexchange-2013.aspx.
Performing steps for site rollover
In the event of a site outage, the steps that you need to take to failover the DAG depend
upon the type of namespace model you have in place, as well as other technologies such as
Anycast DNS or geo-load balancing. For simplicity, these steps assume that technologies such
as those mentioned are not in use, and manual DNS changes will need to be made.
1. Failover mailbox databases to the secondary site. This involves Stop-DatabaseAvail-
abilityGroup and Restore-DatabaseAvailabilityGroup if using DAC Mode as a multi-site
DAG should be (though it is not the default).
2. Changing DNS both internally and externally to point to the IP associated with the
load balancer virtual IP in the secondary datacenter.
Planning certificate requirements for site failovers
As Exchange 2013 uses Internet protocols for all client connectivity, every name used by Exchange Server in client connectivity should be listed on a single digital certificate. This means
that a certificate used by Exchange should include autodiscover.domain.com. It should also
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include the namespace used for the primary site, as well as each protocol if using protocol
independent namespaces and the secondary site namespaces.
The same certificate should be used on all servers because the HTTP authentication cookie
that CAS generates when the user first logins is generated using the certificate on the server.
When the load balancer directs that user connection to a different CAS server, as stateful connections are not required, the authentication cookie can be read as the same digital certificate is installed, and so the user is not required to authenticate again. Also, digital certificates
are not licensed per server, and so the purchase of one certificate can be exported, with the
private key, from the machine it is created on. It can then be imported onto all of the other
Exchange CAS servers. Any Exchange mailbox only server role can use the self-generated
certificate because clients do not connect directly to the mailbox role services. The same is
true of certificates on the Exchange Back End website on a multi-role server as this website
correlates to the mailbox server role. Whereas, the Default Web Site correlates to the CAS role
and will require a trusted certificate bound to it.
Therefore, if you have a network such as that shown in Figure 2-15, you would generate
the following certificate:
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autodiscover.contoso.com
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newyork.contoso.com
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dallas.contoso.com
FIGURE 2-15 A bound namespace model with multiple datacenters and sites where users connect to their
local namespace
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Compare the above with a network that supports a single namespace and a file share witness in a third site. This would need a certificate with either:
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autodiscover.contoso.com
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mail.contoso.com
Or, if using per-protocol load balancer checks:
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autodiscover.contoso.com
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mail.contoso.com
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ecp.contoso.com
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oa.contoso.com
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eas.contoso.com
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oab.contoso.com
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mapi.contoso.com
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ews.contoso.com
Predicting client behavior during a rollover
The exact behavior of any given client during planned switchover or unexpected failover
can be determined by valid testing of the client. This testing should take into consideration
the firmware or software version of the client because different products and versions will
respond in different ways (specifically ActiveSync clients).
Let us consider some points of interest that will help predict what you should expect to
see during rollover of the service to a secondary site, so that testing with real hardware and
software is likely to validate your decisions.
DNS caching As all connectivity to Exchange Server is over IP protocols, and these
protocols are reached by the way of a DNS hosted FQDN, the longer a client caches an out
of date IP address for a given domain name, the longer the client will fail to connect. In the
event of a failure where you are using DNS round robin for availability (not recommended as
there is no service awareness with DNS round robin), if the client caches a single IP address
for a given DNS FQDN and that IP goes offline, the duration of the cache impacts the clients
time without connectivity. If the client caches all of the DNS addresses returned to it, as do
the majority of modern clients, loss of connectivity to one IP means a second IP can be used
without downtime.
DNS round robin load balancing Clients that support multiple record caching or very
short DNS caching work with DNS round robin based load balancing. The only problem with
DNS round robin is that servers that are not responding correctly at the application layer
(even though they are responding to ping etc. at the TCP layer) will still be connected to the
client, and so the client needs to be aware of what constitutes correct service. If the client sees
a valid TCP connection but invalid data at the protocol layer, they need to discard that IP ad-
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dress and try another one. This requires intelligence built into the client. The latest versions of
web browsers and Outlook will do this to the TCP layer, but not to the application layer.
Layer four load balancers When the client is connected to Exchange Server by the way
of a layer four load balancer, and when a server goes offline, the load balancer stops connecting users to it. From a DNS perspective there is only one IP address for a namespace, and it
becomes the load balancers responsibility to keep clients connected. When a server fails the
user is abstracted from this because the connection from the client to the load balancer stays
up. From the perspective of the load balancer, the loss of a TCP session to the real server that
it is load balancing constitutes a loss of service. There is no intelligence in the higher layers of
the TCP protocol stack.
NOTE HEALTH CHECKS Some load balancers will use the health checks discussed in the next section with layer
four, TCP-only services. If the single check that they implement to a real server goes offline
at the application layer (layer seven), they disconnect the server at layer four (the TCP layer)
and seamlessly direct users to a working real server.
Layer seven load balancers Some load balancing products that sit between the client
and the real server can also operate at the application layer. This allows them to understand
the application request and deal with it appropriately. From an Exchange Server viewpoint
this typically means forwarding the Exchange URLs to Exchange Server and blocking requests
to the servers that would be invalid.
Exchange Server 2013 supports a health checking service that load balancers can make use
of to ensure that they are connecting their clients to real servers that are actually working. In
the case of Exchange Server 2013, each HTTP protocol has a URL called Healthcheck.htm that
returns a 200 response code when the checked service is operating correctly. Status code 200
means that all is okay for HTTP. A single load balancer can be configured to check the status
for multiple endpoints and make a decision on whether or not the real server that it is load
balancing is available. For example, if the managed availability service of Exchange Server for
Outlook Web App determines that OWA is not functioning properly on a given server, then
/owa/healthcheck.htm on that server will not respond with 200 OK. When the load balancer
sees this response it will take the server or maybe just requests that attempt to go to /owa
away from the client. The load balancer will continue to check the health of the real server
and when it comes back online again will add it back to the load balancing pool. Figures 2-16
and 2-17 show two different load balancing products and their user interfaces for setting the
monitoring options.
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FIGURE 2-16 Setting OWA health checks on a Kemp load balancer
FIGURE 2-17 Setting OWA health checks on a JetNEXUS load balancer
Redundant load balancers The aim of both layer four and layer seven load balancers is
to abstract from the client the state of the real server they are connecting to, and to ensure
that loss of a server does not result in loss of a client’s ability to connect to the real server. But
what happens when the load balancer fails, or as load balancers are typically available as virtual machines, what happens when the host machine fails and takes down the load balancer?
Typically you would install two load balancers as a failover pair. One load balancer is active
for the IP addresses that Exchange is being published across, and the other in the pair is
passive. The two load balancers check the state of the other frequently, and the passive load
balancer takes ownership of the virtual IP in the event of failure of the primary. Configuration
within the load balancer says what happens when the passive comes back online. The virtual
IP is represented at the network layer with a mac address that moves between the devices as
required. As long as the switch in front of the load balancer can cope in a timely fashion to
the switching of the mac address from one port to another, the client is not impacted during
load balancing failover.
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Geographically redundant load balancing When your datacenters are geographically
separate you need to ensure that the load balancing devices are able to take ownership of the
shared virtual IP in the event of an outage. In the case of geo-load balancing, if the primary
load balancing pair go offline, as the datacenter is offline, the secondary load balancer sees
this by way of a shared communication and updates the DNS record to point to their virtual
IP. The load balancers are configured to provide DNS resolution for requests by the client. In a
geo configuration, for say mail.contoso.com, either a new zone called “mail” is created within
“contoso.com” and that zone is delegated to the load balancer cluster, or the record
mail.contoso.com is a CNAME for a record in the zone hosted by the load balancer such as
mail.geo.contoso.com, where geo.contoso.com is a zone that is delegated to the IP address of
the load balancer (as shown in Figure 2-18). Then the IP address for mail.geo.contoso.com is
the virtual IP from the working load balancer. When the working environment fails, the
mail.geo.contoso.com record becomes the virtual IP of the load balancer in the second
datacenter.
FIGURE 2-18 Configuring a delegation in Windows DNS to support geo-load balancing
Objective 2.2: Design, deploy, and manage a site-resilient CAS solution
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Thought experiment
Patching Exchange Servers
In this thought experiment, apply what you’ve learned about this objective. You can
find answers to these questions in the “Answers” section at the end of this chapter.
You are the network administrator of Contoso Pharmaceuticals and you have
Exchange 2013 servers distributed across four sites. Each site has its own disaster
recovery datacenter that office staff would relocate to in the event of their site becoming unavailable. Each database has four copies, two in the primary site and two
in the DR site. The file share witness is located in a datacenter in a different region.
1. In the event of a single server failing, no databases become active in the DR site.
But in the event of two servers failing at the same time, some databases become
active in the DR site. What namespace do you need to have on your ExternalURL for servers in the DR site to ensure that users can connect to their database
without issue?
2. In the event of a full site outage, planning has shown that Exchange can be
brought online before users could reach the DR site to start work. Therefore,
what namespace considerations do you need to make to ensure that users can
connect to Exchange?
Objective summary
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The CAS role always routes a client to the mailbox server hosting the active copy of the
database where their mailbox is located.
The CAS role proxies all connections to the correct mailbox server, using the same
protocol as the client, after the client authenticates and the CAS role has queried the
Active Directory to access the user’s mailbox information.
Cross-site connectivity is much simpler in Exchange Server 2013 as the RPC protocol is
not used outside of the active mailbox server. The RPC protocol typically requires low
latency on the network and is susceptible to issues when high latency occurs. That was
always a possible issue with Exchange 2010 when your CAS server was in one site and
the mailbox had failed over to another.
A single namespace is a possibility with Exchange Server 2013 due to this change in
protocols used between servers.
Options for site resilience need to take into consideration the namespace used, that
is, if it is bound to a given datacenter or unbound (where the same namespace is used
everywhere).
It is recommended to use the same certificate across all CAS role servers (or multirole
servers, where you are setting the certificate on the CAS role specifically).
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Objective review
Answer the following questions to test your knowledge of the information in this objective.
You can find the answers to these questions and explanations of why each answer choice is
correct or incorrect in the “Answers” section at the end of this chapter.
1. You need to request and install a digital certificate for the four client access servers
that will be used in your Exchange Server 2013 deployment. (Choose all that apply.)
A. Run New-ExchangeCertificate on each CAS server
B. From the Exchange Admin Center generate a new certificate request for autodis-
cover.yourdomain.com
C. From the Exchange Admin Center generate a new certificate request for autodis-
cover.yourdomain.com and all of the names used by all of the CAS servers in all of
the datacenters
D. Purchase a UCC digital certificate from a trusted third-party certificate authority
E. Delete the default certificate configured by the Exchange installation
2. You are creating a plan to ensure that if an Internet link failure occurs at your primary
datacenter, and you successfully move your mailboxes over to the DR site, that all
users will be able to connect. You want to do this with the least IT management tasks
required. (Choose all that apply.)
A. Ensure that all ExternalURLs for all protocols are mail.contoso.com.
B. Ensure that OWA has its ExternalURL set to mail.contoso.com but that all other
protocols have ExternalURL set to null.
C. Configure your internal DNS server to have an A record for each CAS server in
both sites listed with their own IP address.
D. Configure your internal DNS server to have an A record for mail.contoso.com that
has the IP address of your load balancer that load balances Exchange Servers in the
primary datacenter as the IP address of this A record.
E. Configure your external DNS server to have an A record for each CAS server in
both sites listed with their own IP address.
F. Configure your external DNS server to have the externally NATed IP address of
your load balancer that load balances Exchange Servers in the primary datacenter.
Objective 2.3: Design, deploy, and manage site
resilience for transport
So far in this chapter, you have considered site resiliency for mailbox databases with database
availability groups, and client access servers by using consistent URLs and load balancers. The
final service to consider is the transport services, or more specifically the SMTP protocol.
Objective 2.3: Design, deploy, and manage site resilience for transport
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In Exchange 2010, the transport service was a role that you could co-exist with other roles
or, though it was not recommended, install as a dedicated role. In Exchange 2013, as server
hardware is at a point where installing the roles all on the same server is better, the transport
role has disappeared as an installation option, but still exists on both the CAS role and the
mailbox role. Because it is a role within Exchange Server 2013, we need to consider it for siteresiliency.
This objective covers how to:
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Configure MX records for failover scenarios
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Manage resubmission and reroute queues
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Plan and configure send/receive connectors for site resiliency
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Perform steps for transport rollover
Configuring MX records for failover scenarios
Email delivery in Exchange Server uses a number of different configuration options such as
send connectors to deliver email away from a server or receive connectors to accept email
onto a server. For both of these connectors, and for inbound and outbound connectors in
Office 365 (which is covered in a later chapter), mail exchanger (or MX) resource records play
an important part.
When an email is being sent from the Internet to Exchange Server (or any other email
system), you either need a configuration known as a smarthost or MX records in public DNS.
A smarthost value is the name or IP address of the server that you want to send the email to.
This is controlling mail flow directly. To avoid managing how everyone on the Internet wants
to send you email on an individual basis, if you publish in your public DNS zone an MX record
that ultimately resolves to the IP address of your inbound email server, users on the Internet
can email your users easily.
When you create an MX record in DNS you need to provide the following:
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You need to provide an A record in DNS that resolves to the external IP address of
the system that receives email for your domain from the Internet. If you have a spam
and virus filtering service in front of your Exchange Server, the IP address will be the
external IP address of this device. If you have a cloud hosted spam and virus filtering
service that you have subscribed to, you do not need to create the A record as the
filtering company will have created it already, but you will need to know the name of
this A record.
You need to provide an MX record created in your domain, typically with no host
name, that uses the A record created above. If you have a spam and virus filtering
cloud service in use, they will provide you with the A record.
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You also need to provide a priority value. This is a number that you allocated to each
MX record and which control the order that multiple records, if you have them, are
used.
In Figure 2-19 you can see the MX record creation dialog box from a Windows DNS server.
This dialog box shows that the MX record for contoso.com has a priority of 10 and points to the
Microsoft cloud hosted spam and virus filtering service called Exchange Online Protection (EOP).
The value for the MX record in this case is provided by EOP to the Contoso administrators.
FIGURE 2-19 Adding an MX record in DNS
Different public DNS providers will have different ways for you to add MX records, but
they will all require these three pieces of information. If you are hosting your own mail server
or SMTP filtering service on premises it is important to note that the A record that the MX
record refers to must be an A record (or AAAA for IPv6 records) and cannot be a CNAME
record.
When a sending SMTP server wants to deliver to your domain, they look up the MX record in public DNS for your domain, resolve this to the IP address of the A record, and then
connect to that IP address. This can be tested using the command line with Nslookup. The
command line to type is nslookup -q=mx domain.com. Figure 2-20 shows you an example
output.
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FIGURE 2-20 Nslookup output for an MX record query
You can see from this figure that there is an MX record of priority 10 and that resolves to
three A records each with a different IP address. This is only one way to do high availability
of SMTP services, because an SMTP server will automatically pick one A record from the list
(usually the first one) and connect to that server. If that server does not respond, the next
record on the list will be used. Within an Active Directory site, Exchange Servers use the same
technique to connect to other servers. They resolve the IP addresses of all the Exchange mailbox servers in the site and then connect to one of them, and if that fails, connect to another.
You do not need MX records within the Active Directory site, but the principle of connection
is the same.
Behind each of the multiple IP addresses that this example MX record points to could
be an SMTP server, or it could be a load balancer and a considerable number of servers. As
SMTP manages its own load balancing you can publish a single IP per server on your external
firewall direct to each inbound SMTP server that is able to receive from the Internet. If you are
short of available IP addresses, you would use a load balancer. A load balancer can be used to
remove connections from a server that is not responding, or to keep the number of connections across all of your servers about the same, but with SMTP it has its own retry functionality built into the protocol, so it is not always required.
In addition to having multiple A records behind a single MX record, you can have multiple
MX records each pointing to a different SMTP host. If these records all have the same priority
value, they will be used equally by the sending SMTP server. Imagine for example a domain
with three MX records, all with priority 10, with the following hosts:
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mail-us.contoso.com
A
131.107.2.200
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mail-gb.contoso.com
A
131.107.6.150
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mail-hk.contoso.com
A
131.107.9.99
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When this domain is queried for its MX records using Nslookup, this would result in the
answer shown in Figure 2-21.
FIGURE 2-21 Nslookup response to an MX query with more than one MX record
You can see from Figure 2-21 that each MX record is shown, and each A record IP address
is shown. As DNS in this example is a DNS server that supports round robin, each A record
and associated IP address will be returned in a different order each time. Therefore, each querying SMTP server would connect to the first returned IP address and send its email. Though
as you can see from the example, this would mean that inbound emails would be distributed
across the world irrespective of the sending server or the recipient because the first IP address returned to the sending SMTP server is done by DNS and is irrespective of the source or
destination of the email.
Taking the above example, if the Hong Kong office was the primary office and the London
and New York offices were to be used to receive email if the Hong Kong office went offline,
you would either give mail-hk.contoso.com a higher priority than the other two records, or
decrease the priority of the other two records. When talking of MX records, the lower the priority value, the higher the priority of the server. This means that an MX record with a priority
of 10 will be connected to before any MX record with a priority of 20. The MX server with a
priority of 20 will only be connected to when the 10 priority server does not respond. This can
be seen in Figure 2-22. In this figure the Hong Kong office has a priority of 10 and the other
two offices have decreasing priority (i.e. the numbers increase). Therefore, inbound email via
MX record lookup will always go via mail-hk.contoso.com.
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FIGURE 2-22 Nslookup showing different priority results for an MX record lookup
NOTE MX PRIORITY AND SPAM FILTERING
It is a common theory that spam generating malware and the like, lookup the lowest priority MX record and deliver to that server on the premise that there might be less rigorous
filtering, if any, on the server that is used for mail flow backup.
There is also a theory that a way to reduce your inbound spam is to publish an invalid
server as your first MX record. Real SMTP servers will fail to connect and move onto the
next lower priority server, but malware-generating spam will move onto another recipient.
Both of these theories are the opposite of each other and both will probably reduce inbound spam to some degree, but a good quality spam and virus filtering service is a must
for any company.
Therefore, for inbound site resilient email delivery, you should have multiple MX records
each of different priorities with the highest priority/lowest value being the A record to the
primary server.
When you use a spam and virus-filtering service, there are different techniques to direct
email to your preferred server after they have been sent through the filter, and to automatically use a secondary server in the event that the first becomes unavailable. The exact
configuration will depend on the vendor of the server, but adding multiple smarthosts or IP
addresses with a priority similar to that used in MX records is a common implementation.
Microsoft Exchange Online Protection uses a different technique for emails that clear
the filter and are due to be delivered onward to an on-premises server. In Exchange Online
Protection the outbound connector is used and the smarthosts value used to determine the
IP address of the target server. If the smarthosts value is a name (and not an IP address), this
name will first be looked up as an MX record, and then secondly resolved as an A record. This
means that you can add a single smarthosts value that can be priority based. This is done by
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creating multiple MX records for inbound email that are different than the MX record for your
domain (as that needs to point to Exchange Online Protection) either by creating an MX record for a hostname in your domain, or for a separate domain. In Figure 2-23 you can see the
output from two Nslookup commands, the first for the domain and the second for onprem.
contoso.com. The MX for contoso.com goes to EOP and the MX for onprem.contoso.com goes
to mail-hk.contoso.com with a priority of 10, and if that is offline mail-gb.contoso.com as that
record has a lower priority. In EOP the smarthosts value for the outbound connector would
be onprem.contoso.com.
FIGURE 2-23 MX records for EOP and a site resilient EOP smarthost
In this example, EOP will deliver all filtered email to 131.107.9.99 (mail-hk.contoso.com) as
the smarthost value in the connector reads onprem.contoso.com. If mail-hk goes offline, it will
automatically use mail-gb.contoso.com, but while the mail-hk host is online it will never use
the mail-gb host.
Managing resubmission and reroute queues
Within Exchange Server 2013, MX records are not used to deliver email between DAGs, sites,
and servers. Instead a list of all the mailbox servers in the target DAG, or if not DAG, the
target Active Directory site are used in a round robin fashion for connecting to. Each connection that a given transport server makes is logged into the connectivity log files. There
is a connectivity log file for each transport service including FrontEndTransport on the CAS
and Hub and Mailbox Transport on the mailbox role. An example of a connectivity log file
can be found at C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\Logs\Hub\
Connectivity for the transport service on the mailbox role. If a server is not responding and
it is selected as a target for SMTP connections, this will be logged in the connectivity log as
an attempt to connect. Because the connection will fail, the source server will pick another
server, if there is another available, and connect to it. Therefore, for very simple and easy site
Objective 2.3: Design, deploy, and manage site resilience for transport
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and cross-site resiliency in Exchange Server, you should have more than one mailbox role (or
multi-role) server per Active Directory site that you have Exchange Servers located in.
EXAM TIP
It is always a good idea to have an understanding of least cost routing. Exchange Server
only uses the least cost route to deliver messages, and so understanding the impact and
where messages are likely to queue is a good candidate for an exam question. More information on least cost routing can be found at http://technet.microsoft.com/en-us/library/
aa998825.aspx.
In the event that all the target servers in a DAG or site are offline, or the target network is
unavailable, Exchange Server will attempt delivery to the nearest server to the point of failure.
This is done by taking the Active Directory site link costs to the target site, or to the site that
contains the nearest member of the target DAG, and connecting to the first available server
along that least cost path. An example of this is shown in Figure 2-24. In this figure you can
see five sites for a European company where the faster network, and therefore the Active
Directory replication links, go through Paris. For fault tolerance, there are slower backup links
direct to some regional offices, but with more costly Active Directory site links, they are not
used unless the lower cost link is unavailable. The Zurich site is down so the Exchange Server
in Zurich is unreachable. A user in London sends an email to a recipient whose mailbox is on
the Zurich server. The least cost path for this email to take is London to Paris to Zurich, which
would have a cost of 20. All other possible routes would have costs of 50 or higher and so
Exchange Server will not use them because it only uses the least cost route. Remember that
though the least cost route is calculated, Exchange Server will still attempt to connect directly
to the target server in the destination site or DAG before any server on the route.
FIGURE 2-24 Least cost routing when a site is unavailable
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Therefore, with Zurich being offline, the connection from London direct to Zurich will fail
and so the Exchange Server in London will connect to one of the two Exchange Servers in
Paris. If the Zurich site remains offline for a while, further emails from London to Zurich will
begin to queue approximately evenly across both servers in Paris. Emails from Madrid and
Berlin will also take the least cost route, which for them is the route via Paris. This means that
emails from Berlin and Madrid senders will also queue in Paris. The direct links from Berlin
and also from Madrid to Zurich are more expensive than the links via Paris, and so are not
used.
On the Paris servers, the messages will queue and the queue will be retried every minute
for five minutes, and then every 10 minutes until the messages time out at two days. Once
the Zurich site is back online and the Exchange Server in Zurich is able to receive connections
from Paris and the other sites, mail flow will resume within the retry time of 10 minutes.
Using Exchange Management Shell and the Retry-Queue cmdlet, a retry can be forced
rather than waiting for the next retry interval. The next retry interval can be determined by
using the Get-Queue cmdlet.
Considering Figure 2-24, imagine a scenario where the link from Paris to Zurich is unavailable, but the site is up and the separate links from Berlin and Madrid are online. In this
scenario, email from London will still queue in Paris, but email from Madrid and Berlin will
connect successfully. This is because although the least cost route from, for example, Madrid
is Madrid to Paris to Zurich as a cost of 20, the Exchange Server in Madrid will make a direct
connection to the server in Zurich and successfully connect.
The only way to get the emails queued on the Paris servers (from Paris and London senders) to Zurich while the link is down, would be to either change the cost of the Paris-Zurich
link to more than 40 (so that the cost of the Paris to Berlin to Zurich link is less expensive), or
to remove the Paris-Zurich link.
If you remove the link rather than increase the cost, note the following:
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■■
The Paris, Madrid, Zurich link, which also has a cost of 40, will not be used because
the Paris, Berlin, Zurich link will be chosen as the least cost route. This is because both
Paris, Berlin, Zurich and Paris, Madrid, Zurich cost 40. Therefore, the hop count is used
to choose the least cost route. In this example though, both routes have two hops and
so a single least cost route has not been determined. When more than one route has
the same least cost, and as there is still more than one route with the same hop count,
the route that has the lowest alphabetical site name will be chosen. Therefore, in this
example Paris, Berlin, Zurich will always be the least cost route over Paris, Madrid,
Zurich given the above costs and hop count because Berlin is lower alphabetically than
Madrid.
When any link cost or other factor that is used to determine least cost route is
changed, only new messages are automatically evaluated for these changes. Existing
messages already queued on a server have passed through the routing stage of the
server and are waiting to connect to the determined next server. Their route will not
automatically be recalculated.
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■■
The IP networking and routing is the same as the Active Directory site links. London
does not have a direct site link to Zurich and so cannot connect to Zurich directly.
There is no valid route from London, but there is a valid route to the other sites, and so
Paris can be connected to.
To fix this issue without fixing the problem with the Paris-Zurich routers and link, the ParisZurich connector could be increased in cost from 10 to 100 (Set-ADSiteLink Paris-Zurich-ExchangeCost 100). If this was to happen, new emails from London would go London to Berlin to
Zurich at a cost of 60, and emails from Paris would go Paris to Berlin to Zurich at a cost of 40.
The London server would still attempt to connect directly to the Zurich server, but as it does
not have connectivity, it would now connect to Berlin as that is the hop before Zurich on the
least cost route, unlike Paris which was the previous hop when the link costs were lower. Once
queued at Berlin, it would connect successfully to Zurich and bypass the broken connection
between Paris and Zurich.
If London had IP connectivity direct to Zurich, there would be no need to change the costs
as the messages would not queue in Paris.
In the above scenario where messages from London and Paris are queued on the Paris
server and the cost of the Paris-Zurich link is changed to 100, you will also need to force the
emails in the queue to be recalculated for routing so that they can be sent to Berlin. To do
this, you would use the Retry-Queue –Resubmit $true cmdlet. For example, if you ran GetQueue you might see 100 emails queued for the Zurich Active Directory site with a Queue ID
of PARIS1\1234, where PARIS1 is the server name and 1234 is the queue ID. In this case, you
would change the cost of the Paris-Zurich connector and then run Retry-Queue PARIS1\1234
–Resubmit $true. In the example shown in Figure 2-24, you would need to repeat this cmdlet,
with the correct queue ID on PARIS2 as well (for example Retry-Queue PARIS2\554 -Resubmit
$true where 554 is the queue ID on server PARIS2). This can be seen in Figure 2-25.
FIGURE 2-25 Resubmitting messages that are queued after site link costs changed
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In the event that there are messages queued on a server, and you need to take that server
down for maintenance, in Exchange Server 2013 there is the Redirect-Message cmdlet. This
cmdlet will actively move messages from one Mailbox server (that is where the transport
queue lives) to another server. To use Redirect-Message, you need to stop the server receiving inbound messages; otherwise, when the redirection is complete, it will be able to accept
new messages again. Once the redirection is complete, you can run the required maintenance
on the server knowing that the server will not be a valid target for incoming messages.
There are two cmdlets needed to take a server into maintenance from a transport perspective. These are:
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Set-ServerComponentState <SourceServerName> -Component HubTransport -State
Draining -Requester Maintenance
Redirect-Message -Server <SourceServerName> -Target <TargetServerName>
Shadow and poison queues are never redirected to the other server. Therefore, for site
resiliency, ensure that any server that is taken down for maintenance is back online as soon as
possible. That server might contain shadow messages for other servers in the delivery group
that, in the event of loss of those other servers or lagged copy rollback, this server might be
needed for. Shadow messages are always stored on another server in the same delivery group
as the receiving server. The delivery group is either other servers in the Active Directory site
(if the server is not a member of a DAG), or other members of the DAG, or if the DAG has
members on more than one site, the members of the DAG in the other site. For more details
on shadow redundancy, see later in this chapter.
Planning and configuring send/receive connectors for site
resiliency
As you have seen in the previous sections, you add additional MX records or IP addresses for
the same host that the MX record uses to provide site resiliency for inbound email from the
Internet. Within Exchange Server, you just need to have more than one mailbox role server to
receive email from other Exchange Servers.
On the Exchange Server itself there are numerous receive connectors to accept the inbound email. The default receive connectors are as follows:
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Client Access Role:
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Default Frontend Servername
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Outbound Proxy Frontend Servername
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Client Frontend Servername
Mailbox role:
■■
Default Servername
■■
Client Proxy Servername
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Unlike Exchange 2010, there is no requirement to configure any settings to receive anonymous
emails that are destined for your Exchange organization This requirement isn’t needed because
the Default Frontend Servername receive connector accepts anonymous connections by default.
As each client access role server has a receive connector that accepts anonymous connections, configuring inbound mail flow for site failover scenarios comes down to load balancer
or MX, server name or IP address configuration. For inbound email from the Internet, you
need to have a way to ensure that when a site goes offline, that the standby site can take over
emails easily. This is best done with two or more MX records of differing priority as discussed
earlier, though geo-load balancers can be used as well for larger deployments.
For internal mail flow that starts outside the Exchange organization, for example application servers and devices that generate email notification and reports, these need to be
configured with the IP address of an Exchange client access role server because these servers
have the frontend transport service and anonymous submission should you need it. The
problem with configuring applications and devices with an IP address is that you need to
change it on all of the applications and devices when failover occurs, or when you upgrade to
a newer version of Exchange, or add new servers. Therefore, the best way to control mail flow
within the network inbound to Exchange is to use an MX record and an A record pointing to
multiple IP addresses, and to use an FQDN that resolves to this MX or A record within the applications and devices.
This FQDN allows the IP to be changed in the event of a failure in the current target server,
or to have multiple IP addresses and to make use of the native load balancing within the
SMTP protocol. If you have applications or devices that can only take an IP address, or if you
have multiple IP addresses in an A record and this negatively impacts these applications, you
should use a load balancer to distribute the load and to allow simple failover to a different
server or site in the event of an outage, or when it comes time to migrate to a new server.
Performing steps for transport rollover
In the event of an outage of either a CAS or mailbox role server, there may be impacts to
message delivery that will need resolving, or impacts to messages that were in the queue on
the server that failed.
In the event of server failure, any technology that directs connections to an alternative
server will be sufficient. As discussed in previous sections of this book, this can include load
balancers, or for inbound emails, more than one MX record or more than one IP for the MX
or A record being used. In scenarios where you have one or more of these systems in place,
new connections made after the time of failure will fail to connect to the box suffering outage, but will succeed in connecting to alternative servers.
If a message was currently in transit, a different scenario needs to be looked at first. All
mail flow into Exchange Server 2013 should go via a client access server, and receive connectors on mailbox servers should not be modified to receive external traffic. When an email
is received by the frontend transport service on a CAS role server, listening on TCP port 25,
the initial connection is made and the SMTP headers accepted. Upon receiving the RCPT TO
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header, the frontend transport service queries the Active Directory to determine the mailbox
database of these recipients. If these recipients are mailboxes, the frontend transport service
makes a connection to the DAG or site (if the mailbox is not in a DAG) that contains the active
mailbox copy. If there is more than one recipient, an evaluation of up to the first 20 recipients is made to determine which DAG or site should be used for the majority of these first 20
recipients. If the recipients are distribution lists or other mail objects (mail users, and so on), a
connection is made to a mailbox role server in the same site as the CAS server.
Once this connection is made, the body of the message is passed through the CAS frontend transport service without further modification or inspection. It is passed to the selected
mailbox role server and the transport service on that server.
Upon being received by this transport service on the mailbox role server, and before the
sending server in front of the CAS role has received any acknowledgement of receipt, the
transport service connects to another transport service in the same delivery group. That is, if
this is a cross-site DAG member, it will attempt to connect to a member of the same DAG in a
remote site. If the DAG is not cross-site, or there is no response from up to four remote DAG
members, it will connect to a DAG member in the same DAG and same site. If the mailbox
server is not a DAG member, it will attempt to connect to up to two servers in the local Active
Directory site. These values for cross-site and local site retries can be configured via Set-TransportConfig and can be seen in Figure 2-26.
FIGURE 2-26 Get-TransportConfig showing shadow redundancy related settings
Once connected to a second transport service on another mailbox server in the same
delivery group, a copy of the message, the shadow message, will be sent to this server to be
kept for two days (or the ShadowMessageAutoDiscardInterval from Get-TransportConfig if
this has been changed). The second transport server acknowledges the first for successful receipt of the shadow message. The first transport server acknowledges the frontend transport
proxy service of successful receipt of the message and then, and only then (unless connections time out), does the frontend transport service acknowledge the sending SMTP server.
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This sequence of events means that should a server fail during receipt of a message or
receipt of the shadow, the preceding server will reconnect automatically to redeliver.
Once the transport service has the message in its queue, it will connect to the mailbox
transport service on the server containing the active copy of the mailbox. The message is
handed to the mailbox transport service over SMTP to port TCP 475 on the actual server
holding the active mailbox. If this server should fail during delivery, the holding transport
server can redeliver. If the holding transport server should fail while queuing this message,
the shadow holder will promote its copy of the message to the primary copy and deliver
it should it not receive acknowledgement of successful delivery from the primary transport
service after three hours. Three hours is the ShadowHeartbeatTimeoutInterval x ShadowHeartbeatRetryCount, or 12 x 15 minutes = 3 hours.
Both the transport service holding the primary copy of the message, and the shadow copy
of the message persist the message in the mail queue database for two days. This persistence
of the mail queue database is known as the Safety Net. In the event of delivery failing to the
database, or the database failing over to a passive copy of the database and suffering loss of
log files, and therefore loss of messages, the copy of the message in the transport mail queue
database (the Safety Net) can be redelivered automatically.
In the event of a lagged database copy being mounted without being replayed, for
example in the case of logical database corruption such as an active deletion of data or
virus outbreak, the mail queue database can replay up to its stored duration and so result
in minimal data loss even though the database has been rolled back in time. Therefore, it is
important that the duration of time that the mail queue database stores messages, which is
two days by default, equals or exceeds the ReplayLagTime value on a mailbox database copy.
The SafetyNetHoldTime parameter on Set-TransportConfig defaults to two days and can be
increased as the ReplayLagTime can be up to 14 days.
Thought experiment
Configuring send connectors
In this thought experiment, apply what you’ve learned about this objective. You can
find answers to these questions in the “Answers” section at the end of this chapter.
You are the network administrator of Northwind Traders Inc. and you have a CRM
and sales application that sends invoices and receipts by email following an online
purchase.
1. How would you configure any connectors in Exchange to ensure all invoices and
receipts are journaled before onward delivery, and that a single server outage
does not stop the delivery of these invoices and receipts?
2. What permissions would you need to set on the connector to allow relay of messages to the Internet? (There are three possible answers here.)
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Objective summary
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Use a single MX record and multiple A records if you have a single site and multiple
servers. If you have more than a handful of servers, a load balancer is usually a better
option and a single IP address on the MX record.
For smarthost values use a FQDN rather than an IP address because it is easier to manage change in the longer term.
For multiple sites with inbound SMTP connectivity, either use a cloud hosted filtering
service that can direct users’s email to the correct site, for example using conditional
routing in EOP. If there is no facility in the cloud filtering service, or a cloud filtering
service is not an option, use the highest priority MX record for the primary site.
For message resubmission, remember least cost routing. Understanding this will help
you determine the servers that will queue messages given specific site, network, and
server failures.
Use the -Resubmit parameter of Retry-Queue in the event that you want queuing
emails to be reevaluated for new routes if changes have been made that will change
the least cost route to a target site or DAG.
Take a look at http://vanhybrid.com/2013/11/28/script-putting-exchange-server2013-into-maintenance-mode/ for a script that will help you place a server into maintenance mode.
Exchange Server 2013 should have no requirement to modify receive connectors for
anonymous submission. For authenticated client submission, the recommendation is to
use port 587 and not 25. Authentication on port 587 will allow relay if the authentication is successful.
Set-TransportConfig is used to configure the shadow redundancy timeouts and settings such as whether to use a cross-site DAG or only to use the same site (regardless of
DAG node location).
Ensure that any lagged database has a ReplayLagTime of less than or equal to the SafetyNetHoldTime.
Objective review
Answer the following questions to test your knowledge of the information in this objective.
You can find the answers to these questions and explanations of why each answer choice is
correct or incorrect in the “Answers” section at the end of this chapter.
1. Contoso wants to have a 7 day lagged database copy and wants to ensure that their
SafetyNet duration is set to the same value. What command would they use?
A. Get-TransportService | Set-TransportService -SafetyNetHoldTime 7Days
B. Get-TransportService | Set-TransportService -SafetyNetHoldTime 7:00.00
C. Set-TransportConfig -SafetyNetHoldTime 7Days
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D. Set-TransportConfig -SafetyNetHoldTime 7:00:00
2. Which of the following accepted domains can be included in an email address policy?
A. Authoritative
B. InternalRelay
C. OpenRelay
D. External Relay
3. Contoso and Fabrikam are two divisions of the same company. Both were historically
separate entities and remain so for email due to compliance reasons. Both organizations have an Exchange Server 2013 deployment in two different datacenters and they
use rack space at the partner company’s datacenter to host passive DAG nodes. They
would also like to use the Internet connection of the partner in the event of an outage
with their own connection for inbound mail flow. What do they need to configure in
addition to the records pointing to the primary datacenter?
A. Create the following DNS records:
contoso.com MX 5 mail.fabrikam.com
fabrikam.com MX 5 mail.contoso.com
B. Create the following DNS records:
contoso.com MX 10 mail.fabrikam.com
fabrikam.com MX 10 mail.contoso.com
C. Create the following DNS records:
contoso.com MX 20 mail.fabrikam.com
fabrikam.com MX 20 mail.contoso.com
D. For each organization, create an internal relay accepted domain and a send con-
nector with the matching address space as the accepted domain.
E. For each organization, create an external relay accepted domain and a send con-
nector with the matching address space as the accepted domain.
Objective 2.4: Troubleshoot site-resiliency issues
This objective of the site resiliency chapter looks at different troubleshooting options to
consider for diagnosing and finding faults within the items that we have looked at throughout
this chapter.
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This objective covers how to:
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Resolve quorum issues
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Troubleshoot proxy and redirection issues
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Troubleshoot client connectivity
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Troubleshoot mail flow
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Troubleshoot datacenter activation
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Troubleshoot DAG replication
Resolving quorum issues
For your database availability group to be online and able to mount databases it must have
quorum. That is to say it must have a majority of servers in the cluster online. If it does have
exactly the minimum number of servers required to reach majority, then the file share witness
will have a file locked on it to add an additional vote and maintain quorum. This ensures that
should the DAG drop to an equal number of nodes online and offline (or unreachable), the
DAG will stay online in the primary site. With the file share witness it means you will always
have one datacenter in a multi-site DAG that should be able to reach quorum and the other
site would fail to reach quorum. Datacenter Activation Coordination (DAC) mode is an additional check within a DAG to ensure that not only does a majority need to be present but
nodes must contact another node with their DACP bit set to 1 before being able to mount
their databases. DAC mode is disabled by default but should be enabled on all DAGs with two
or more servers.
When you have an outage that takes away a single DAG node, you are taken closer to not
having quorum. When quorum is lost, all the databases in the cluster dismount. Therefore,
it is important to understand quorum and ensure that network outages and maintenance
events would not place you in a position of losing quorum. In Windows Server 2008 R2,
quorum is calculated as a majority of the total number of nodes in the cluster and unless you
evict nodes from the cluster (as you do in a failover event with Restore-DatabaseAvailabilityGroup) your majority is always calculated from the total number of nodes in the cluster that
are online or offline. In Windows Server 2012 R2, as individual servers go offline, the total
node count for majority is recalculated and therefore majority can remain with fewer nodes
online. Note that this feature, called dynamic quorum, is enabled by default in 2012 R2 but is
available in Windows Server 2012.
Troubleshooting quorum is therefore a knowledge of the operating system in use under
Exchange Server, the total or online number of nodes and what half + 1 of this count is because half + 1 is the majority.
To find out your cluster configuration in the DAG you can use PowerShell commands such
as Get-Cluster, Get-ClusterNode, and Get-ClusterQuorum. Some of these are shown in Figure
2-27.
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FIGURE 2-27 Cluster reports via Windows PowerShell
Troubleshooting proxy and redirection issues
All client connectivity to an Exchange 2013 mailbox happens through the Client Access Server
role. The CAS role is an intelligent proxy server for Exchange Server clients. It authenticates
the client or determines the recipient of the mail message and forwards the network traffic to
the server that is active for that mailbox (the server that’s hosting the active/mounted copy of
the database with the user’s mailbox in it). Therefore, if client connectivity to a 2013 mailbox
is failing there are two places to consider. The first is the CAS role and the second is the mailbox server that is active for that user’s mailbox. If you have multiple CAS role servers, the first
step to troubleshoot is to use a different server. If you have a load balancer make sure that it
is configured to detect individual protocol health issues and redirect clients when Exchange
managed availability updates the Healthcheck.htm file for each protocol.
If the CAS servers are working okay and are able to proxy the connection to a mailbox
server, but there is still no connectivity, you would troubleshoot issues with opening the actual mailbox. Also consider using various protocols to see if it was protocol specific. Exchange
Server can quarantine mailboxes that introduce performance issues to the server and a
mailbox in quarantine would be unavailable, whereas other mailboxes on the same database
would be working fine.
MORE INFO MAILBOX QUARANTINE
More details on mailbox quarantine can be found at http://technet.microsoft.com/en-us/
library/jj218650(v=exchg.150).aspx.
When the mailbox is located on a legacy Exchange Server and the client connects to a CAS
2013 server, the CAS 2013 server will prefer to proxy the connection to the target Exchange
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version unless the connection is to OWA on an Exchange 2007 server, or to OWA or ECP on
an Exchange 2010 server with the External URL set. In these two cases the CAS 2013 server
will redirect to the legacy URL for OWA 2007, and the External URL for OWA/ECP 2010.
Exchange 2013, apart from the two cases above, will proxy to the FQDN of the 2007 or 2010
Exchange Server. Therefore, for legacy Exchange connectivity each Exchange Server needs
to be able to connect directly to the FQDN of each legacy server in the organization. It is
worth pointing out that firewalls between Exchange Servers and other Exchange Servers and
domain controllers are not supported.
MORE INFO PROXY AND REDIRECTION
Much more detail on proxy and redirection can be found in the Exchange Team blog at
http://blogs.technet.com/b/exchange/archive/2014/03/12/client-connectivity-in-anexchange-2013-coexistence-environment.aspx.
Troubleshooting client connectivity
When you have client connectivity issues, the first piece of troubleshooting is to see the scope
of the issue. Does it affect everyone, or one person, or somewhere in between? Once you
have a scope to the issue you can look for something that might be common between all of
the users. For example, are they all in the same database or site or something that would allow you to tie the connection issue to something you can go and investigate?
For client connectivity, another great tool is the ability to use multiple client types to connect to Exchange Server. For example, if Outlook is having an issue, do you get the same with
OWA? If SMTP is having an issue, what about IMAP or POP3, if you are using a client that uses
these protocols? If you can limit connectivity issues to a given client type, that will help. For
issues where clients cannot connect, but you are able to open a web browser and login to
OWA, start troubleshooting at any recent changes and consider settings and configuration
such as AutoDiscover as part of client troubleshooting because OWA does not need AutoDiscover (unless you are using OWA for Devices on the iPhone/iPad or Android phone because
AutoDiscover is used by these apps).
Once you have a scope of the issue, and a client that the problem is exhibited in, you are
a good way to looking for an answer. Always examine the event viewer logs on a server to
see if an issue is caused by something that might be surfaced in the logs, and always be very
careful about making changes to fix issues without a good understanding of the issue first, as
a change could compound the problem.
Troubleshooting mail flow
To understand and troubleshoot mail flow is to understand the SMTP protocol, which Exchange Server services do what, and what the connectors and other configuration items are
used for.
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Troubleshooting connectors
Receive connectors in Exchange Server are the SMTP server. To send email into and across an
Exchange Server organization, email is accepted by a receive connector. When there is more
than one receive connector on a target machine, the connectors need to be configured so
that they either listen on a unique IP address or port (the connectors binding) or that they
answer for specific ranges of IP addresses. Troubleshooting for specific bindings is easy. As
long as you can make a connection to the binding IP and port, you know connectivity is
working. But how can you tell if you have connected to the right receive connector when the
connector is supposed to answer you based on your source IP address? The easiest way to do
this is to configure the banner property of the receive connector. The banner is the message
that starts with 220 that you receive when you connect to a receive connector. If you set each
receive connector on a server to a unique value, you can clearly tell which receive connector
you have reached when you connect to it on its listening IP address and port.
Once you have made a successful connection to the listening IP address and port, it is also
useful to be able to enter the commonly expected SMTP verbs by way of a telnet session. To
open a session using the telnet client to a remote Exchange Server, use telnet remote_IP_address port. If you were trying to connect to server 131.107.2.200, you would type telnet
131.107.2.200 25 and you would expect to see 220 and the configured banner, or if it’s the
default banner, you would expect to see 220 and the server name and date/time. Once you
have connected, use the EHLO domain.com command to say hello to the remote server and
to tell it your domain name. It should respond with 250 OK or 250-SomeSMTPVerbs and then
250 VERB. The last line will read 250 space verb. All of the other lines will read 250 hyphen
verb.
After the supported verbs are returned, try MAIL FROM: [email protected] and
then RCPT TO: [email protected] When telnetting into Exchange Server on
port 25, you cannot enter an external email address unless you are connecting to a receive
connector that allows for relay.
The DATA command follows the successful entry of the MAIL FROM and RCPT TO commands. You can have one MAIL FROM and one or more RCPT TO commands. One DATA command ends the message envelope and moves onto the message body.
In the message body, enter To:, From:, and Subject: all with valid values after the colon and
each on their own line. After Subject: have a blank line to end the headers, and then type the
message body. Finish the message with a period on a line on its own followed by QUIT.
If in any of the verbs typed previously, you do not get the expected response, (for
example the response shown in Figure 2-28), you have further troubleshooting to do. The
most common reason why an anonymous connection will fail to an Exchange Server is if
the server is out of resources such as disk space or memory and is known to be in a state
called backpressure. A look in the event logs will give the reason. When this is resolved,
mail flow will automatically resume.
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FIGURE 2-28 Using telnet client to successfully connect to an Exchange Server receive connector
MORE INFO EVENT LOGS AND BACKPRESSURE
The website at http://technet.microsoft.com/en-us/library/bb201658(v=exchg.150).aspx
covers more details on the entries found in the event log during backpressure.
Outbound connectors, or send connectors on the transport service, will queue messages
that cannot be delivered. All of the other send connectors on other services are stateless and
do not queue messages. Therefore, if there is a problem with a send connector that uses a
Frontend CAS to proxy through, it will queue in the transport service. If the destination is offline or otherwise unavailable, the message will queue in the transport server that holds the
send connector to that destination. If the transport service is offline, the mailbox transport
submission service, which delivers messages between the mailbox and the transport service,
will not queue and the message will stay in the outbox in the client.
EXAM TIP
Different clients will use different folders to send email from. They will not always use the
Outbox. Messages that are being sent from OWA will stay in Drafts until they are sent and
messages in Outlook cached mode will use Sent Items to send the email from (unless you
are disconnected). Outlook in online mode uses the Outbox as its delivery folder.
When messages are queued on the transport service you can use Get-Queue or GetQueueDigest to review the queue on a given machine, or across all of the machines in the
DAG or site. Get-Queue | Format-List LastError will return the last error on any given queue.
Sometimes you will not get an error on a queue, but will get errors on the messages in the
queue, and for this you need to use Get-Message | Format-List LastError instead.
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Troubleshooting transport services
In Exchange Server 2013, there are a number of transport services. These are as follows (with
the process name in brackets) and the role the service runs on listed as well:
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Mailbox server role
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Transport (EdgeTransport.exe)
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Mailbox transport delivery service (MSExchangeDelivery.exe)
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Mailbox transport submission service (MSExchangeSubmission.exe)
Client Access Server role
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Frontend transport (MSExchangeFrontendTransport.exe)
The frontend transport and the two mailbox transport services are stateless, that is they
proxy messages and do not store them on disk. Frontend transport finds the correct mailbox
server to proxy the message to, that is it will deliver the message to any server in the same
DAG or site (if not a DAG member) as the active mailbox and to any local mailbox server in
the same site for messages going to legacy servers or distribution groups.
If frontend transport is not running, TCP port 25 will not be listening on the CAS server.
The transport service on the mailbox server will listen on TCP 25 if it is a mailbox only role
server, but on TCP 2525 if it is co-located with a CAS role server, so that CAS only listens on
TCP 25. You cannot have two services listening on the same port, though in Exchange 2013
it is possible to build receive connectors on the transport service that listen on port 25 when
CAS is also listening on that port. This can cause lots of issues, so ensure on all co-located
servers that you always bind receive connectors to frontend transport service.
The mailbox transport services send messages to databases (mailbox delivery) and receive
from the mailbox databases (mailbox submission). If either of these services are offline then
sending or receiving from the database will not occur.
NOTE HEALTH MANAGER
Exchange 2013 comes with the Health Manager service. The job of the Health Manager is
to check the health of Exchange, such as can it log into OWA, or send and receive emails,
and so on, and if not, to fix the issue. Often this will involve restarting services and can
involve blue screening the server to force a reboot (in the event that the disks are not responding). Therefore, it can be the case that the issue is gone by the time you get a report
about it, because the Health Manager will have started or restarted the service for you.
Therefore, look up maintenance mode for Exchange Server because that is how you tell
the Health Manager not to restart stuff or attempt to fix stuff if you have the server offline or
partially offline on purpose.
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Troubleshooting transport-related configuration
Change is usually the biggest cause of outages in IT systems. For example, someone has
changed something and now something is broken. For transport, the objects that you need
to configure to ensure valid mail flow typically work until something changes in them or the
send to or receive from targets change, such as a smarthost of firewall rule changes and now
the smarthost is unreachable.
Always have change control and keep a record of all configurations before they are
changed and after they are changed. In Exchange Management Shell (and Windows PowerShell in general), this is easy to implement with the use of Start-Transcript and then at the
end Stop-Transcript. This records everything you do to a log file. Therefore before you make
changes, for example to an Accepted Domain, you would run Get-AcceptedDomain | fl to
write to the screen and also to the transcript log file, the configuration you have in place at
this time. Then make your changes. If you need to role these changes back, you have what
you need to role it back to.
If you use ECP to make changes, remember that the admin audit log can be queried to
show you what you have changed, but it will not show you what it was before the change was
made!
Troubleshoot datacenter activation
If you have a site failover and you need to activate passive copy databases in your secondary datacenter, you need to ensure that you use the Stop-DatabaseAvailabilityGroup and the
Restore-DatabaseAvailabilityGroup cmdlets. This adds the servers that are part of the cluster in
the failed site (Stop-DatabaseAvailabilityGroup -ActiveDirectorySite PrimarySiteName) to the
DAG stopped servers list, and then the Restore cmdlet evicts them from the cluster and reduces
the node count so that majority can be obtained in the secondary/surviving datacenter.
Unless you have the file share witness in a third site that the secondary datacenter can
access and the primary cannot, you must do manual processes like the one described here to
perform a failover to the other site. With a file share witness in the third site that both sites
have independent access to, you can have automatic failover as long as both sites hold an
even number of cluster nodes and at the point of failure, the primary site goes down, but the
third site with the file share witness does not then automatic failover occurs as majority is
maintained.
If you do not have DAC mode enabled, which you should on a two or mode node DAG,
then you need to use cluster commands to assist in the failover process. With DAC mode, as
well as stopping split-brain scenarios, this allows you to use Exchange cmdlets only to manage
the DAG instead of needing to know the additional cluster commands as well.
Objective 2.4: Troubleshoot site-resiliency issues
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Troubleshooting DAG replication
Unless it is otherwise changed, DAG replication occurs over port 64327.Therefore, this port
should be open for connectivity between nodes of the same DAG, though of course it is not
supported to have any firewall between any Exchange Server and it can generate unexpected
results.
For the Database Availability Group, replication happens on the replication network if
one has been designated. Ports need to be open for this connectivity on the network that
Exchange expects it to be on.
To see the state of the replication of your DAG, use Get-DatabaseAvailabilityGroup to find
the DAG settings. Use Get-MailboxDatabaseCopyStatus to find the state of the replication and
which servers are active for which databases, such as. which server the database is mounted
on. The copy and replay queue lengths, described below, should ideally be low (<10) unless
you are looking at a lagged database, which will have a high replay queue but should still
have a low copy queue.
The Get-MailboxDatabaseCopyStatus cmdlet will return the database status of the local
machine and show the health of the database. One server in the DAG should have the database Mounted, and other servers should have the database Healthy. Disconnected and other
states should be investigated. From Figure 2-29, you can see Get-MailboxDatabaseCopyStatus
run against the local server (with no additional parameters) and against a remote server (GetMailboxDatabaseCopyStatus -Server servername).
FIGURE 2-29 Get-MailboxDatabaseCopyStatus against two servers in the same DAG
Figure 2-29 shows that the databases that are working are mounted on the second server
in the output and healthy on the first with no copy queue or replay queue. One database is
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offline and has an unreachable source database, hence the large number of items to copy, which is actually showing an error rather than real count of logs outstanding.
Using Get-MailboxDatabaseCopyStatus, you can find out the count of transaction logs that
are created on the server that holds the mounted, or active, copy of the database and that
need to be shipped to all the other copies of the database. They are copied from the active
copy to each passive copy. There is no passive-to-passive copying. It is important to note that
if you have multiple passive copies of a database on the far side of a WAN link, the logs will
be copied once per passive copy and will require double or more bandwidth.
Use Get-MailboxDatabaseCopyStatus on each passive copy to see the log copy status. If a
server is behind on its log copy, it will have a higher than expected value. You should troubleshoot the log replication process from the active to that passive server.
Once logs arrive on the passive server, they are inspected for integrity and copied again
if they fail the inspection. They are then written into the passive database replica. If there are
issues writing the log into the database, for example on a disk with poor write speeds, the
replay log count will increase. On a lagged database copy, there will always be a replay queue
length of the number of transaction logs generated in the time window that the database is
lagged by. On a server with a generally consistent level of activity and mail flow, this number
will generally be the same from one day to the next at the same time of day. It will fluctuate
over the day and week because the active copy will change in terms of its activity levels. For
a lagged database copy, consider the values of the replay queue length that you expect and
ensure that these are not massively over your expectations.
If you have a large copy queue length or a large replay queue length on a passive server,
you will need the disk space to store these logs. For a large copy queue length, it will mean
the logs are not removed from the active copy even if the active copy is backed up. Always
attempt to fix the copy or replay issue rather than manually deleting log files. If you delete a
log file that is required by a passive copy of that database, you will most likely have to reseed
the entire database.
Thought experiment
Planning namespaces
In this thought experiment, apply what you’ve learned about this objective. You can find
answers to these questions in the “Answers” section at the end of this chapter.
You are the network administrator of Alpine Ski School. An avalanche has hit your
office and it is now destroyed. You want to recover Exchange Server in your DR site
down the mountain. The top-of-the-mountain Active Directory site is called MountainTop and the DR site is called Basecamp. What do you need to do?
Objective 2.4: Troubleshoot site-resiliency issues
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Objective summary
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A DAG needs to maintain quorum for databases to remain mounted in it. You looked
at ensuring that maintenance, patching, etc. do not cause an entire DAG outage due to
less than the majority of the DAG nodes remaining online.
Unexpected failures can happen. Do not actively shutdown servers for maintenance
that will bring you close to losing majority.
If you evict servers from a cluster and therefore from the DAG, you will need to copy
the entire database back to that server when you add it back into the DAG unless all
of the log files containing all of the changes are still available on the active node. Do
not remove servers from clusters unless there is a site failover or the end of the server’s
role within the DAG.
For the most part, Exchange will proxy connections through the CAS role to the active
mailbox server or to a legacy server in the same Active Directory site as the mailbox.
There are only a few occasions where a redirection occurs and these are for OWA 2007,
where the user is redirected to the legacy namespace (which is required), and OWA
2010 where the user is redirected to the ExternalURL if one is set.
In the case of redirecting from Exchange 2013 to Exchange 2010 with an ExternalURL
set, you will need to authenticate again if you are running a lower cumulative update
release.
Use the Health Manager service and Managed Availability to try to ensure that Exchange Server remains functional and healthy, and to failover databases and restart
services/servers to try and resolve issues.
Use the Get-MailboxDatabaseCopyStatus cmdlet to know the copy status of your databases and to help ensure your databases remain with their replicas up to date.
Objective review
Answer the following questions to test your knowledge of the information in this objective.
You can find the answers to these questions and explanations of why each answer choice is
correct or Incorrect in the “Answers” section at the end of this chapter.
1. Which of the following Windows PowerShell commands will return the list of servers
and the state of the servers in a cluster?
A. Get-ClusterNode
B. Get-ClusterServer
C. Get-Cluster <Name> | FL *node*
D. Cluster.exe Node
2. You notice that when using Get-MailboxDatabaseCopyStatus on a server that hosts
only passive database copies, you have a large copy queue length of over 10,000 logs
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for one of these databases. Which of the following could be the potential impacts of
this issue?
A. Backups will not truncate log files.
B. Disk space for logs might run out.
C. The active database might dismount.
D. The transaction logs on the lagged copy will auto play forward.
3. What does the RCPT SMTP verb do?
A. It tells the SMTP server to send a read receipt.
B. It tells the SMTP client to send a read receipt.
C. It tells the SMTP client that the email has been received.
D. It tells the SMTP server the email address of the recipients of the email.
Objective 2.4: Troubleshoot site-resiliency issues
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127
Answers
This section contains the solutions to the thought experiments and answers to the objective
review questions in this chapter.
Objective 2.1: Thought experiment
1. You can switch off three servers in the primary site or one server in the primary site
and both servers in the secondary site.
2. To prevent outage in the event of a non-resilient WAN failure during server mainte-
nance, a single node can be successfully taken offline at a time. If any server in the
secondary site in unavailable, you are limited to a single server in the primary site.
Different combinations of answers are available based on the number of servers that
are online at any given time, and the Mailbox Role Calculator is a great tool for helping
you understand these numbers for a given scenario.
Objective 2.1: Review
1. Correct answer: C
A. Incorrect: Resume-DatabaseAvailabilityGroup is not a valid cmdlet.
B. Incorrect: Start-DatabaseAvailabilityGroup is used to restart the DAG in the failed
site that is back online again. It is not used to reduce the DAG to just the secondary
site and bring the DAG online in the event of a failure.
C. Correct: The correct commands are Stop-DatabaseAvailabilityGroup followed by
Restore-DatabaseAvailabilityGroup.
D. Incorrect: The question says the alternative witness server has already been set so
it is not needed to be set again, but if it was needed it would be set as a property
of the DAG with Set-DatabaseAvailabilityGroup –AlternateWitnessServer.
2. Correct answer: C
A. Incorrect: This answer does not meet the requirement for a failure scenario be-
cause all of the databases would go online in Madrid in the event of a site outage.
B. Incorrect: This answer would result in an outage of servers or sites failing to Tokyo
or San Francisco. If the failure was a network failure that isolated Madrid mailboxes, these users would come online in the other data centers and not where the
users are located.
C. Correct: Each user population needs a DAG that in the event of failure comes
online in their nearest datacenter. If a failure occurred in any of the other answers
there would be a scenario where some users’ mailboxes would come online in a
site that the user could not access.
D. Incorrect: This is not a valid DAG design. All servers that hold a replica of a data-
base must be in the same DAG.
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Objective 2.2: Thought experiment
1. As each site with its associated DR site is geographically separate you can use the
bound namespace model and bind a namespace to each region. For example, the UK
region would be mail-uk.contoso.com and the US region mail-us.contoso.com. The unbound model would work (mail.contoso.com for everyone) though this would depend
upon factors not described in the question. As Exchange 2013 does not have an RCP
connection between servers you can connect to a CAS proxy in the primary site and
successfully reach a server in the remote site. The ExternalURL in the DR site should be
the same in the primary site.
2. Because you have the files share witness in a third site, you can bring Exchange online
in the DR site automatically. You only need to make sure that the DNS A record for the
namespace points to the load balancer in the DR site. If you have a geo-load balancing solution, this would happen automatically; if not, you would need to change the IP
address once for that region’s namespace.
Objective 2.2: Review
1. Correct answers: C and D
A. Incorrect: This will create a self-signed certificate on the server that contains the
servers name only and will not be trusted.
B. Incorrect: This answer does not include all of the names that the certificate needs
to have.
C. Correct: This answer is the first part of the answer. The certificate will be used on
all CAS servers and so this one certificate needs to have all of the names used by
Exchange on it.
D. Correct: This answer is the second part of the answer. A trusted certificate needs
to be purchased and the request created in C will be used to create this certificate.
2. Correct answers: A, D, and F
A. Correct: Using a single ExternalURL means only two names needed in the certifi-
cates. That will be mail.contoso.com and autodiscover.contoso.com.
B. Incorrect: If this were done, only OWA would be available externally. Other pro-
tocols like Outlook Anywhere and Exchange Web Services would not be available
externally.
C. Incorrect: Each CAS server needs to be registered in DNS for management pur-
poses, but for client connectivity you would need to add the Exchange namespace
record to DNS as well.
D. Correct: This answer ensures that internal users connect to Exchange via the load
balancer and not directly or individually to one server via its FQDN.
Answers
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129
E. Incorrect: This will result in DNS round robin load balancing, which means remov-
ing the records manually from DNS when servers stop responding. This requires a
lot of hands-on management.
F. Correct: This answer ensures that external users connect to the load balancer serv-
ing the Exchange Server via the IP address that they can reach from outside of the
network.
Objective 2.3: Thought experiment
1. The business has a requirement to journal the invoices and receipts; they are sent
through Exchange Server rather than directly using an SMTP relay. Therefore, you
would need a receive connector configured, preferably on more than one server
and either round robin DNS records to list the IPs of these multiple servers and use
the FQDN of this A record in the CRM and sales application, or you could use a load
balancer in front of Exchange with a virtual IP for TCP 25 that connects to an available
Exchange Server. To ensure journaling of all email, you would create a journal rule and
not use the journaling property on a mailbox database.
2. There are three possible ways to do this:
A. Configure the application to have a username and password of an account in the
Active Directory that has a mailbox and then connect to TCP port 587 to send
email. This will require an authenticated connection but relay is already available
on this connection.
B. Create a new receive connector with Externally Secured permissions on the
frontend transport service on a few CAS servers. Ensure that the RemoteIPRange
parameter of the connector is set to the IP addresses of the CRM and sales application. And finally ensure that relay permissions (accept any recipient) are granted to
the connector.
C. Create a new receive connector with anonymous permissions on the frontend
transport service on a few CAS servers. Ensure that the RemoteIPRange parameter
of the connector is set to the IP addresses of the CRM and sales application. And
finally ensure that relay permissions (accept any recipient) are granted to the connector.
Objective 2.3: Review
1. Correct answer: D
A. Incorrect: SafetyNet duration is a global setting and not set per server. The value
for the SafetyNetHoldTime parameter is also incorrect.
B. Incorrect: SafetyNet duration is a global setting and not set per server.
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C. Incorrect: The value of SafetyNetHoldTime is written as a timespan value. Times-
pan values are Days:Hours:Minutes. This answer uses a string value and so is incorrect.
D. Correct: SafetyNet duration is a global setting and not set per server or database.
Therefore Set-TransportConfig is used.
2. Correct answers: A and B
A. Correct: Authoritative domains can be included in an email address policy.
B. Correct: Internal relay domains can be included in an email address policy.
C. Incorrect: OpenRelay is not a valid accepted domain type.
D. Incorrect: External Relay domains cannot be included in an email address policy.
3. Correct answers: C and E
A. Incorrect: This answer would route all emails during normal working times to the
wrong datacenter.
B. Incorrect: This answer would distribute emails across both datacenters all the
time.
C. Correct: This answer adds a lower priority MX record that would only be used
when the higher priority record server has gone offline.
D. Incorrect: As the question covers two different organizations there is a choice of
which accepted domain to include. The internal relay allows the email address of
the other company to be added to email address lists and email addresses in the
other domain given to users in the first domain. This is not required by the scenario and so this is not the best answer given the options.
E. Correct: This answer allows for emails to be accepted by the other partner and
forwarded to the first partner, queued if necessary, but without accidently opening
the possibility of having an email address list with this domain listed on it.
Objective 2.4: Thought experiment
1. Check the copy queue length on the passive databases. This will give you an idea of
possible data loss.
2. Remove the cluster nodes in the office that is out of use. You can do this using Stop-
DatabaseAvailabilityGroup -ActiveDirectorySite MountainTop -ConfigurationOnly. This
will not connect to the servers in the MountainTop site (as they are unreachable) but
write to the local domain controller that they are out of the cluster should they ever
come back online again.
3. Then you would run Restore-DatabaseAvailabilityGroup to evict the nodes in the
MountainTop site from the cluster and reduce the cluster node count to just the servers in the Basecamp site (that is, the other site).
Answers
Chapter 2
131
4. If the number of outstanding transaction logs is 12 or less, the databases will mount. If
it is more than 12, you will need to issue the Mount-Database database_name command. On the databases mounting, any time window of lost logs will be requested
from the SafetyNet database automatically to attempt to reduce data loss. The transport service database (mail.que) in the Basecamp site will have a copy of all the recent
messages as shadow redundancy defaults to ensuring messages are shadowed to the
other site the DAG is located in.
Objective 2.4: Review
1. Correct answer: A
A. Correct: Get-ClusterNode returns the nodes in the cluster and their status with
regard to being up or down.
B. Incorrect: This PowerShell cmdlet is not a valid cmdlet.
C. Incorrect: This PowerShell cmdlet does not contain information about the cluster
nodes.
D. Incorrect: This is a cmd prompt executable and not a PowerShell cmdlet. It does
return the same information as the correct answer and the exe can be run in a
PowerShell window, but it is not a PowerShell cmdlet as required by the question.
2. Correct answers: A, B, and C
A. Correct: As there will be log files that have not been copied to a passive copy they
cannot be truncated by backup. This is expected behavior when you have a copy
queue length that exceeds 100 logs.
B. Correct: This is also correct. You should have enough disk space on the server with
the active copy to store enough logs to cover your largest expected network outage - which is the most likely reason for a large copy queue length.
C. Correct: If you run out of disk space on the active log folder then if the active da-
tabase shares that drive, you run out of disk space for the database too, which will
cause the database to shutdown.
D. Incorrect: The playing forward of any lagged copy happens when the lagged copy
disk space runs out and not when the active copy is short on disk space.
3. Correct answer: D
A. Incorrect: The Notify verb is used for receipts.
B. Incorrect: SMTP verbs are sent from the client to the server.
C. Incorrect: The SMTP server tells the SMTP client that the message has been re-
ceived with a 250 response to the data termination period or the BDAT verb.
D. Correct: RCPT is the recipient verb in SMTP.
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Index
A
AADSync 282, 302
Active/Active (Multiple DAG) model 81
Active/Active (Single DAG) model 81
active calls viewing 51
Active Directory 104, 348
Active Directory Certificate Services (AD CS) 193–194
Active Directory Federation Services (AD FS) 294
designing 295–296
server configuration 297–299
server role 298
troubleshooting 349
Active Directory forests 328
Active Directory Rights Management Services
(AD RMS) 2–3, 33, 145, 164–179
Outlook Protection Rules 172–174
template creation 165–168
transport decryption 174
transport protection rules 169–172
troubleshooting 194–195
Active Manager, 68
ActiveSync 93, 177, 322
AD FS. See Active Directory Federation Services (AD FS)
admin audit log 123
AdminDisplayVersion property 182
administrator audit logs/logging
configuring 181–182
interpreting 184–185
Allow BitLocker With A Compatible TPM Group Policy
option 140
AlternateWitnessServer parameter 74
Anonymous Calendar Sharing 310, 312–313
anonymous emails 112, 115
anonymous sharing policy 312–314
anti-malware engine 175
application layer 96
ArchiveDomain value 214
archived policy templates 166
archive keys 194
archive mailboxes 203–204
archives/archiving 203–222
configuration of 205–216
enabling for user 210–211
for cloud mailboxes 208–211
for on-premise mailboxes 213–216, 220
for remote mailboxes in hybrid mode 211–213
names 215
policy creation 216–220
storage for 220–221
A records 101-106, 112
AuditAdmin property 181
audit logs/logging
administrator 181–182, 184–185
exporting 184
interpreting 182–185
mailbox 180–181, 183–184
viewing 183
Audit Logs role 184
authentication 95, 118
BitLocker 139
connector 325
cookies 95
digital signatures 146–148
OAuth 288, 293
on port 587 115
password based 143
web proxy 309
authoritative accepted domains 334, 335
auto attendants 3–4, 12–18, 26
configuration of 15–18
creating 13–15, 18
defining 13
features provided by 12–13
359
AutoDiscover
AutoDiscover 92, 172, 317, 322, 329, 331–332, 336
autodiscover.domain.com 94
automatic failover 79
Automatic Replies 264
Automatic Speech Recognition 3–4
Azure Active Directory 280, 306–308, 348
Azure Active Directory DirSync 154
Azure Active Directory Rights Management Services 33
Azure Directory Synchronization 282, 349
Azure RMS 144, 145
B
backpressure 121
backup networks 84
backup software 82
banner property of receive connector 120
Banner property 325
bi-directional availability 328, 329
BitLocker 138–141
Network Unlock 139
Windows Server 2008 R2 and 141
BitLocker Drive Encryption feature 140
bound namespace model 95
brute force attacks 143
built-in role groups 195
C
calendar availability 306
Calendar folder 239
calendar sharing 318
call answering rules 2–3, 26
configuration of 18–21
as administrator, via PowerShell 20–21
self-service, as user 19–20
call logs viewing 50–51
call monitoring 48–51
call redirection 10
call router 26
configuration of 9–10
call statistics 54
viewing 49–50
certificate authority (CA) 43, 146, 147, 148
Certificate Revocation List (CRL) 158, 189–192
certificates. See digital certificates
CertificateValidation 159
Certificate Validation Failure error 158
ClassificationID 266
360
Click To Run technology 257
client access configuring pre-licensing for 177
client access layer 88
Client Access role 1, 10, 21
Client Access Server (CAS) 65, 74
configuring for hybrid configuration 286
HTTPS access 316
namespaces 88–91
site failovers and 94–99
site resiliency and 88–101
Client Access Server (CAS) role 89, 90, 100, 111, 112,
122, 331
troubleshooting 118–119
ClientAccessServerEnabled 174, 177
client connectivity 89, 94–95
during rollover 96–99
troubleshooting 118–119, 119
client network 84
cloud hosted filtering service 115
Cloud Identity 293
cloud mailboxes archives for 208–211
cluster configuration 117–118
cluster features 75–76
cluster name object (CNO) 82, 85–86
cluster service 72
CNAME record 103
CNO. See cluster name object (CNO)
coexistence 279
cross-forest 327–337
firewall configuration for 323–325
mail flow requirements 325–326
namespaces for 320–322
on-premises, with legacy systems 320–328
with Exchange Online 280–305
Complete-MigrationBatch 343
compliance
In-Place Holds and 247–249
journaling and 249–254
Legal Holds and 246–247
MailTips and 264–265
message classifications and 266–267
solution implementation 260–272
transport rules for 260–263, 268–270
compression network 85
conditional routing 115
configuration
Active Directory Federation Services (AD FS) 297–299
administrative audit logging 181–182
Datacenter Activation Coordination (DAC)
AD RMS 164–165
archiving 205–216
auto attendants 15–18
AutoDiscover 331–332
call answering rules 18–21
cross-site DAG 80–86
DAG networks 83–86
Data Loss Prevention (DPL) 222–234
eDiscovery 244–254
firewalls 323–325
hybrid 280–305
IP gateway 4–9
IRM for discovery 176–177
journaling 249–254
mailbox audit logging 180–181
MailTips 264–265
Managed Folder Assistant 240–241
message classifications 266–267
Message Records Management (MRM) 234–244
mutual TLS with DomainSecure 156–158
MX records 102–107
online archiving 205–216
pre-licensing 177
protected voice mail 34–35
proxy redirect 323–324
retention policies 236–237
revocation settings 189–190
send/receive connectors 111–112, 114
site-resilient namespaces URLs 91–94
single sign-on 293–294, 301–303
S/MIME in Outlook 149–151
transport rules 260–263
UM call router 9–10
UM mailbox policy 35–38
Unified Messaging 4–27
Web Application Proxy (WAP) 300–301
connectivity 349
connectivity log files 107
connectors
inbound 286–287
outbound 107, 121, 286–287
receive 102, 112–113, 115, 120–121, 286–287, 331
send 156, 158–160, 286–287
troubleshooting 120–121
Convert-MsolDomainToFederated 303
CreateDAG.ps1 script 68
CRL Distribution Points value 190
CRLUtil tool 192
cross-forest availability 328–330, 350
cross-forest coexistence 327–337
AutoDiscover design and configuration for 331–332
bi-directional availability 328, 329
certificate and firewall requirements 330
mail flow 330–331
setting up availability 328–330
shared namespaces for 333–337
cross-forest migration 57
cross-site connectivity 89–91, 100
CSV files 341
Cumulative Update 6 216, 284
Cunningham, Paul 91
Custom MailTip 265
cutover migration 279
D
DAGInfo.csv 68
DAGs. See Database Availability Groups (DAGs)
Database Availability Groups (DAGs) 21, 117, 203–204
cross-site configuration of 80–86, 83
Datacenter Activation Coordination (DAC) 66–71
IP addressing 82
network compression 85
network configuration 83–86
number needed 80–81
on Windows Server 2012 and 2012 R2 Servers 85
quorum options 72–79
rediscovering networks 83–84
removing member from 71
replication, troubleshooting 124–125
site resiliency for 65–88
without cluster administrative access point 82, 85
database journaling 251–253
DatabaseList 135
DatabaseRestrictionFilter 136
databases
quorum 72
seeding 66
split-brain conditions 66, 68
datacenter activation troubleshooting 123
Datacenter Activation Coordination (DAC) 86, 117, 123
benefits of 71
enabled 67–69
for DAGs with two members 69–70
not enabled 67
planning and implementing 66–71
workings of 68
361
Datacenter Activation Coordination Protocol (DACP)
Datacenter Activation Coordination Protocol
(DACP) 66, 68, 70
DatacenterActivationMode parameter 68, 86
DATA command 120
Data Loss Prevention (DLP) solutions 222–234
custom policies for 231–232
custom rules for 227–231
designing, for business requirements 231
pre-built rules for 223–227
deep text extraction engine 222–223, 227
Default Frontend Servername receive connector
112–113
default gateways 84
Default MRM Policy 216, 217, 237, 240, 241
Default Sharing Policy 310
DelayedSourcePartyInfoEnabled parameter 6
Delete And Allow Recovery tag 239–240
Desktop Experience 3–4
dial by name function 12
dial plans 4, 13, 41
assigning to users 27–28
creating 23–26
using Exchange Admin Center 24–25
using Exchange Management Shell 25
enabling and disabling features 29–32
moving users between 28
secondary 28
types of 23–24
UM and IP-PBX 23
Dial Plans parameter 11
Differentiated Services Code Point (DSCP) 51
digital certificates 145–151, 323
AD FS server 294, 298
Certificate Revocation List (CRL) 189–192
cross-forest coexistence 330
determining validity of 187–189
expiry date of 188
exporting, with private key 193
for site failovers 94–96
Hybrid Configuration Wizard 289–290
private keys for 192–194
revocation list 192
self-signed 303, 308, 348
updating 322
wildcard certificates 298
digital signatures privacy and 148
digital signing 146–151
Directory Synchronization 281
DirSync 208–209, 212, 215, 282, 302, 349
362
Disable-UMCallAnsweringRule 20
Disable-UMIPGateway 7, 8
discontinued features 343
discovery. See AutoDiscover; See eDiscovery
discovery mailboxes 255–257
Discovery Management group 245
Discovery Management role 176
Discovery Manager 254
discovery managers 176
distributed rights policy templates 166–167
DLP. See Data Loss Prevention (DLP) solutions
DNS caching 96
DNS records 281
DNS round robin
for availability 96
load balancing 96
domain controllers 187
domains
authoritative accepted 334, 335
conversion to federated 303
external relay accepted 334
internal relay accepted 334, 336
DomainSecureEnabled 157
Domain Secure/TLS
configuration 156–158
evaluating 155–162
DomainValidation 159
double-hop migration 339
DSCP. See Differentiated Services Code Point
dynamic quorum 75–76, 77, 117
dynamic witness 75
E
E.164 number 24
EAC. See Exchange Admin Center
Edge role servers 339
Edge Server 334
EdgeTransport.exe 122
eDiscovery 244–260
In-Place federated searches 257–258
journaling 249–254
legal/litigation hold, enabling 246–247
message recipients and 251
multi-mailbox searches in EAC 254–257
query-based In-Place Holds 247–249
RBAC roles for 245
security considerations 245
ExternallyAuthoritative
EDiscoverySuperUserEnabled property 174, 176
EHLO domain.com command 120
EHLO SMTP verb 155
email messages
anonymous 112–113, 115
encryption 146–147, 152–154
message classifications 266–267
resubmission and rerouting of 107–111
send/recieve connectors 101, 111–112, 115, 120–121
shadow 111, 113, 114
signing 146
transport rollover 112–114
troubleshooting flow of 119–123
Enable-ExchangeCertificate 48
Enable-RemoteMailbox -Archive 212–213
Enable-UMCallAnsweringRule 20
Enable-UMIPGateway 7, 8
encryption
BitLocker 138–141
Domain Secure 155–162
email 147–148, 152–154
smart cards 142–144
S/MIME 146, 152–154
EncryptionOnly 158–159
Enforce or Test DLP Policy With Policy Tips 228
Enhanced SMTP 155
Enterprise Edition 75
EOP. See Exchange Online Protection (EOP)
ethical walls 260–263
event logs 121
EWS ExternalURL 330
Exchange Admin Center (EAC) 6, 283
auto attendant configuration using 15–17
auto attendant creation using 14–15
commands in 18
creating dial plan using 24–25
disabling Unified Messaging via 31–32
enabling Unified Messaging via 29–31
IP gateway configuration using 7–9
mailbox policy configuration using 37–38
multi-mailbox searches in 254–257
protected voice mail setup using 34–35
viewing call statistics in 49–50
Exchange Back End website 95
Exchange Certificates properties window 44–45
Exchange Control Panel (ECP) 93, 143, 211, 322
creating archives in 212–213
Exchange Enterprise CAL 144
Exchange for SharePoint eDiscovery Center 258
Exchange Management Console (EMC) 283
Exchange Management Shell (EMS) 6, 13, 283
auto attendant configuration using 18
commands 18
creating auto attendant using 18
creating dial plan using 25
disabling Unified Messaging via 32
enabling Unified Messaging via 31
IP gateway configuration using 9
protected voice mail setup using 35
UM call router configuration using 11
viewing call statistics in 50
Exchange Online 90, 205–216, 341
coexistence with 280–305
mail flow 286–287
Exchange Online Archiving 215
Exchange Online Archiving SKU 205–216
Exchange Online licenses 205–216
Exchange Online Protection (EOP) 103, 106–107, 290
Exchange Server
enabling, in hybrid configuration 280
multiple location deployment 80–81
patching 100
phone system in 4–5
prerequisites for 3–4
setting namespace URLs in 93–94
voice functionality 3
voice interface to 2–3
Exchange Server 2003 339
Exchange Server 2007
migration to Exchange Server 2013 320–328, 338–346
Exchange Server 2010
migration to Exchange Server 2013 320–328, 338–346
namespaces in 88–89
Exchange Server 2013
connectivity in 89
health checking service 97
operating systems 75, 77, 117
S/MIME in OWA and 154
Exchange Server 2013 CU6 284
Exchange Server Role Calculator 78
Exchange Trusted Subsystem (ETS) 74
Exchange Web Services (EWS) 93, 172, 322
Export-OutlookClassification.ps1 script 267
ExternalHostname 94
ExternalLicensingEnabled 174
ExternallyAuthoritative 325
363
External Recipients
External Recipients 264
external relay accepted domains 334
ExternalURL 91–94, 287, 322, 323, 330
F
Failover Cluster Management tool 82
failovers
certificate requirements for 94–96
configuring inbound mail flow for 112
configuring MX records for 102–107
predicting client behavior during 96–99
steps for site rollover 94
FAST technology 258
fault tolerance 108
fax support 3–4
Federated Identity 294–295
federation 305–319
Active Directory Federation Services 295–304
certificate and firewall requirements 316
domain conversion 303
metadata 308
Microsoft federation gateway 306–309
organization relationships 316–318
sharing policies 309–315
troubleshooting 348–349
Federation Metadata Update Automation Installation
Tool 303
federation trusts 305–311, 316, 328
creation of 285–286
testing 348
troubleshooting 348–349
file share witness 72–75, 76, 77, 86, 87, 117, 123
Filter Based On Criteria search 247–248
firewalls 53, 119, 292, 295, 301, 316, 323–325, 349
cross-forest coexistence 330
ForceUpgrade parameter 6
forest trusts 328–329
FQDN. See Fully Qualified Domain Name (FQDN)
FrontEndTransport 107
Frontend Transport service 113-114, 122, 331, 347–348
Fully Qualified Domain Name (FQDN) 5, 10, 43, 112, 115
G
Generate Incident Report And Send It To... 231
geographically redundant load balancing 99
geo-load balancing 93, 94, 99, 112
364
Get-Cluster 117
Get-Cluster DAGName | Get-ClusterQuorum | Format-List
73–74
Get-ClusterNode 117
Get-ClusterNode ClusterName | Format-Table Name,
DynamicWeight, State 76
Get-ClusterQuorum 117
Get-DatabaseAvailabilityGroup 124
Get-ExchangeCertificate 48
Get-Help 7
Get-IRMConfiguration 174–175, 176
Get-Mailbox 58, 209
Get-Mailbox -Archive 213
Get-MailboxDatabaseCopyStatus 124, 125
Get-MsolDomain 302
Get-MsolUser 209
Get-Queue 109, 110, 121
Get-QueueDigest 121
Get-Queue | FL LastError 158
Get-Queue <queue_id> | FL LastError 160
Get-RemoteDomain 214, 215
Get-RemoteMailbox -Archive 211
Get-RMSTemplate 171
Get-TransportConfig 113, 156
Get-TransportPipeline 175
Get-UMActiveCalls 51
Get-UMCallAnsweringRule 20
Get-UMCallRouterSettings 11
Get-UMIPGateway 7, 8
Global Address List 12, 17
H
hashes 147, 151
Healthcheck.htm 97, 118
health checking service 97, 98
Health Manager service 122
HELO verb 155
Helpdesk role 20
high availability 21–23, 104
HTTP authentication cookies 95
HTTP protocol 89
HTTP redirection 332
HTTPS 316
Hub and Mailbox Transport 107
Hub Transport 343
hybrid coexistence 280–305
Active Directory Federation Services 295–304
layer seven load balancers
CAS servers for 286
configuration of 281–282
connectors for 286–287
deployment and management 280–291
federated trusts 285–286
OAuth 288
preparing for 282–285
prerequisites for 280–281
single sign-on configuration 293–294
WAP configuration 300–301
Hybrid Coexistence Wizard 280
Hybrid Configuration Wizard 284–294
limitations of 291–293
using 288–291
hybrid mode 211–213
hybrid server license 283
hybrid servers 283
Hyper-V 140
I
ignorenetwork $true parameter 84
inbound connectors 286
inbound fax support 3–4
Information Rights Management (IRM) 33–34, 164–179
configuring for discovery 176–177
enabling 169
evaluating 144–145
testing 170–171
troubleshooting 194–195
information sharing 305–319
policies for 309–315
In-Place Archive 215, 240
In-Place federated searches 257–258
In-Place Holds 247–249, 255
In-Private Browsing mode 284
installation
AD RMS 164–165
UM language packs 38–39
Unified Messaging 3–4
InternalHostname 94
InternalLicensingEnabled 174
internal relay accepted domains 334, 336
InternalURL 91–94
Internet Protocol Private Branch Exchange
(IP-PBX) 1, 4, 22
dial plans 23
intra-forest migration 57
Invalid Internal Recipient 264
IP addresses
configuring applications and devices with 112
for DAGs 82
mail servers 102, 104
WAP/AD FS proxy server 296
IPAddressFamilyConfigurable parameter 11
IPAddressFamily parameter 6, 11
IP AnyCast 93
IP gateway 26
configuration of 4–9
cmdlets 6–7
prerequisites for 5–6
settings 6
using Exchange Admin Center 7–9
using Exchange Management Shell 9
example of 4–5
toolbar icons 8
IRM. See Information Rights Management (IRM)
J
JetNEXUS load balancer 98
journaling
database 251–253
designing and configuring 249–254
Exchange Online 249, 251
Office 365 and 250
on-premises Exchange Server 249
JournalReportDecryptionEnabled 174 , 249
journal reports 250, 253
journal rules 251–252
just a bunch of disks (JBOD) 203–204
K
Kemp load balancer 98
key recovery agent 194
L
language packs 38–41
installation of 38–39, 40
removing 40
viewing installed 39
Large Audience 265
LastDirSyncTime property 209
last man standing scenario 76
layer four load balancers 97
layer seven load balancers 97
365
least cost routing
least cost routing 108–109, 115
legacy systems
decommissioning 59–60
keeping 344
migration 338–346
on-premises co-existence with 320–328
legal/litigation hold 246–247
LicensingLocation 175
load balancing 91, 294, 323
DNS round robin 96
geo 93, 94, 99, 112
geographically redundant 99
layer four 97
layer seven 97
protocol specific 94
redundant 98–99
SMTP 104
troubleshooting 118
LoggingLevel 347
logical database corruption 114
login failure 349
Lync Logging Tool 54
Lync Online 280
Lync Server 2013 257
Lync Server Resource Kit 54
Lync/Skype for business 54
M
mailbox audit logs/logging
configuring 180–181
interpreting 183–184
mailboxes
archive, storage of 220–221
cloud archives for 208–211
coexistence strategy 58
connectivity to 89–90
discovery 255–257
failover 94
for journaling 253–254
migration of 57-58, 341–343
moving between sites 58–59
on-premises, archives for 213–216, 220
quarantine of 118
remote archives for, in hybrid mode 211–213
searching multiple, in EAC 254–257
sharing policies for 310–315
366
Mailbox Full 264
mailbox policies 41
configuring UM 35–38
Mailbox role 1, 21, 65, 90, 111, 122
Mailbox Transport 347
mailbox transport delivery service 122
mailbox transport submission service 121, 122
mail delivery 102
mail exchanger (MX) records
configuring, for failover scenarios 102–107
controlling mail flow with 112
creation of 102–103
cross-forest mail flow and 330
priority 106
shared namespaces and 333
mail flow
controlling 112
cross-forest 330–331
for coexistence 325–326
hybrid configuration 286–287, 289
troubleshooting 119–123, 347–348
MAIL FROM command 120
mail queue database 114
MailTips 264–265
Managed Folder Assistant 240–241
management networks 84
ManagementRole 136–137
ManagementRoleAssignment 135, 137
ManagementRoleEntry 137
ManagementScope 135, 137
Management Shell. See Exchange Management Shell
Management Shell cmdlets 137
MAPI network 84
MD5 algorithm 147
message classifications 266–267
message encryption 146, 152–154
message integrity 148
Message Records Management (MRM) 234–244
custom tags for 237–239
Managed Folder Assistant 240–241
removing and deleting tags 241
retention policies for
assigning to users 239–240
configuring 236–237
designing 234–236
message tracking logging 347
Message Waiting Indicator (MWI) notifications 5
Nslookup
Microsoft Crypto API 147
Microsoft federation gateway 306–309
Microsoft Live ID authentication platform 308
Microsoft Management Console 344
Microsoft Message Analyzer 54
Microsoft Office 365, See Office 365
Microsoft Office 365 Federation Metadata Update Automation Installation Tool 303
Microsoft Online datacenters 348
Microsoft SharePoint integration with 257
Microsoft Shop 2–3
Microsoft stack 2–3
Microsoft Unified Communications Managed API Core
Runtime 3–4
Midsize plan 281
migration
coexistence strategy planning 58
cross-forest 57
cutover 279
decommissioning legacy systems 59–60
determining transition paths 338–339
discontinued features and 343
double-hop 339
intra-forest 57
legacy systems 320–328, 338–346
mailboxes 341–343
moving UM mailboxes between sites 58–59
preparation for 56–57
public folders 339–341
redirecting SIP gateway to Exchange 59
software 339
strategy planning 57–58
to Exchange Online 280–305
transitioning and decommissioning server roles
344–345
Unified Messaging 55–61
upgrading policies 343
missed call notifications 2–3
Moderated Recipient 265
Move-ActiveMailboxDatabase 71
Move To Archive 236
MoveToArchive tags 218
MRM. See Message Records Management (MRM)
MRSProxy setting 287
MSExchangeDelivery.exe 122
MSExchangeFrontendTransport.exe 122
MSExchangeSubmission.exe 122
multi-mailbox searches 254–257
multiple forests 282, 292, 327–328
Mutual Auth TLS 157
mutual Transport Layer Security (MTLS) 155-162
troubleshooting 43–48
viewing installed SSL certificates 43–45
MX records. See mail exchanger (MX) records
N
namespaces
bound namespace model 95
defined 88
for coexistence 320–322
planning 125
shared 333–337
site-resilient 88–91
URL configuration 91–94
network address translation (NAT) 323
network binding order 84
network compression 85
Network Connections window 84
Network Time Protocol (NTP) servers 187
Network Unlock 139
Never Delete retentin tag 238
New-AdminAuditLogSearch 185
New-DatabaseAvailabilityGroup cmdlet 74
New-ExchangeCertificate cmdlet 47
New-ManagementScope 135
New-MessageClassification 171
New-MessageClassification cmdlet 266
New-MigrationBatch 342
New-MoveRequest 343
New-MSOLUser 208
New Organization Relationship dialog box 316–317
New-OutlookProtectionRule 172–173
New Sharing Policy dialog box 311
New-SystemMessage 263
New-TransportRule 161
New-UMCallAnsweringRule 20
New-UMIPGateway 7, 8, 9
NodeAndFileShareMajority clusters 72, 73, 86
NodeMajority clusters 72, 86
nodes needed in cluster 72
non-repudiation 148–149
Nslookup 103–104, 105, 106, 107
367
OAuth
368
O
P
OAuth 288, 293
Office 365 11, 90, 102, 139, 280
Azure RMS i n 144
cross-forest mail flow 331
journaling restrictions and 250
licenses 205–207
online archiving in 205–216
shared namespaces in 337
single sign-on in 294, 301–303
subscription 281
tenant 281
Office 365 Message Encryption (OME) 266
Office ProPlus edition 145
online archiving. See also archives/archiving
licenses 205–207
setting up 205–216
Online parameter 7
on-premises mailboxes archives for 213–216, 220
opportunistic TLS 155
organization relationships 316–318
troubleshooting 348–349
OrgID 307
outbound connectors 107, 121, 286–287
Outlook
configuring S/MIME settings in 149–151
message encryption 152–154
Outlook 2013 Trust Center 149–150
Outlook Address Book 93
Outlook Anywhere 91, 92, 93, 94, 322
Outlook calendar permissions 313
Outlook Protection Rules 172–174, 175
Outlook Voice Access 3–4
Outlook Web App options page 18, 19–20
Outlook Web App (OWA) 3-4, 21, 93, 94, 97, 98,
119–120, 154, 321, 322
Anonymous Features setting 312
configuring to support XML files 184–185
legal hold and 246
S/MIME and 145, 154–155
virtual directory policy 312
Oversize Message 265
passwords 143
[email protected] file 173
Permanently Delete tag 239
permissions 134–135, 195–196
PIN numbers 29, 36, 143
PKI. See Private Key Infrastructure (PKI)
poison queues 111
policy migration 343
Policy Tips 225
POP/IMAP 322
port 587 115
port 5060 6, 10
port 5061 10
port 64327 124
Port parameter 6
port TCP 475 114
PowerShell 6
cmdlets 4
configuration of call answering rules via 20–21
creating dial plan using 25
disabling Unified Messaging via 32
enabling Unified Messaging via 31
preferred architecture (PA) 22
pre-licensing 177
Primary Active Manager (PAM) 74, 87
priority values 103
privacy
digital signatures and 148
S/MIME and 148
Private Key Infrastructure (PKI) 146–147
private keys 142, 146–147, 148, 152, 155, 192–194
protected voice mail 2–3, 33–35, 41
settings 34–35
setup using Exchange Admin Center 34–35
setup using Exchange Management Shell 35
protocol layer 96
proxy layer 89. See also Client Access Server (CAS) role
proxy redirect 323–324
proxy servers 118-119, 292, 295, 297, 309
proxy settings 287
public folder migration 339–341
public keys 142, 146–147, 148, 152–153, 155
RouteMessageOutboundRequireTls
Q
Quality of Service (QoS) 22, 54
configuring 51–52
Packet Scheduler 51
troubleshooting 51, 52–53
quorum 72–79, 86
dynamic 75–76, 77, 117
file share witness and 72–75, 87
loss of 76, 117
scenarios 77–79
troubleshooting issues 117–118
type of 72–73
quorum database 72
R
radio beacon 187
RBAC. See role-based access control (RBAC)
RBAC Permissions management 20
RBAC roles 245
RCPT TO command 120
RCPT TO header 112
Real Time Protocol (RTP) 10, 53
reboot event 70
receive connectors 102, 111–112, 115, 120–121,
286–287, 331
RecipientRestrictionFilter 136
RecipientRoot 135
recovery keys BitLocker 141
recovery point objective (RPO) 21
recovery time objective (RTO) 21
redirection 323–324, 332
redirection issues troubleshooting 118–119
Redirect-Message cmdlet 111–112
redundant array of independent disks (RAID) 203–204
redundant load balancers 98
Registry Editor 52
regular expression (RegEx) filtering 222
remote mailboxes
archives for 211–213
MRS proxy settings 287
Remote PowerShell 143, 144
Remove-UMCallAnsweringRule 20
Remove-UMIPGateway 7
ReplayLagTime 114, 115
replication
networks 83–84
troubleshooting DAG 124–125
Reply All On Bcc 265
reroute queues 107–111
Restore-DatabaseAvailabilityGroup 70, 71, 94, 117, 123
Restricted Recipient 264
resubmission queues 107–111
Resubmit parameter 115
retention hold 246
retention policies
archives 216–220
assigning to users 239–240
configuration of 236–237
designing 234–236
retention tags 235–239
creating 235
custom, creating and configuring 237–239
removing and deleting 235, 241
Retry-Queue 109, 115
Retry-Queue –Resubmit $true cmdlet 110
revocation settings 189–190
Rights Management Services (RMS) 144, 226
implementing 167–168
template creation 165–168
troubleshooting 194–195
RMS. See Rights Management Services (RMS)
RMS CAL for Windows 144
RMS Decryption Agent 176
RMS Encryption Agent 176
RMS Super User 178
role-based access control (RBAC)
evaluating 134–138
exclusive scopes 136
filters 136
management role 136–137
management scope 135–136
permissions 135
role group 137
triangle of power 134–135
troubleshooting 195–196
RoleGroup 137
role groups 195
root domain 187
RouteMessageOutboundRequireTls 161
369
routing
routing
conditional 115
least cost 108, 108–109, 115
RPC protocol 89, 100
RTM (release to manufacturing) version 291
RTP. See Real Time Protocol
S
SafetyNetHoldTime parameter 114, 115
SCP 169
SDP. See Session Description Protocol (SDP)
Search-AdminAuditLog 184
SearchEnabled 174
searches
In-Place federated 257–258
multi-mailbox 254–258
Secure/Multipurpose Internet Mail Extensions (S/MIME)
digital signing 148–151
evaluating 145–155
message encryption 152–154
OWA and 145, 154–155
terminology 147–148
secure token service (STS) 296
security 133–202
Active Directory Rights Management Services (AD
RMS) 164–179
BitLocker 138–141
digital certificates for 146–147
Domain Secure/TLS 155–162
eDiscovery and 245
Information Rights Management (IRM) 144–145
mailbox and administrative auditing 180–185
privacy and 148
role-based access control (RBAC) 134–138
Secure/Multipurpose Internet Mail Extensions (S/
MIME) 145–155
smart cards 142–144, 147
strategy selection 133–164
troubleshooting 186–198
security groups 195
self-signed certificates 303, 308, 348
send connectors 102, 111–112, 114, 121, 156, 286–287
TLS with 158–160
server farms 298
ServerList 135
Server Manager 297, 301
Server parameter 11
370
ServerRestrictionFilter 136
Server Role Requirements Calculator 68
server roles migration of 344–345
service checking 292
service level agreement (SLA) 21
ServiceLocation 174
Service Pack 3 339
session border controller (SBC) 58
Session Description Protocol (SDP) 10
Session Initiation Protocol (SIP) 1, 10
redirecting gateway to Exchange 59
troubleshooting communications 53–54
session keys 153–154, 155
Set-AdminAuditLogConfig 182
Set- cmdlet 347
Set-DatabaseAvailabilityGroup cmdlet 74
Set-FrontEndTransportService 347
Set-IRMConfiguration 169–170, 249
Set-MailboxTransportService 347
Set-MsolADFSContext PowerShell 302
Set-SendConnector 157, 160
Set-TransportConfig 113, 114, 115
Set-UMCallAnsweringRule 20
Set-UMCallRouterSettings 11
Set-UMIPGateway 6, 7, 8
Set-User cmdlet 137
SHA1 algorithm 147, 188
SHA256 algorithm 147
ShadowMessageAutoDiscardInterval 113
shadow messages 111, 113, 114
shadow queues 111
shadow redundancy 111, 113, 115
shared address book 283
shared free/busy 337
shared namespaces 333–337
SharePoint integration with 257
SharePoint eDiscovery Center 258
SharePoint Online 280
sharing policies 309–315
sharing rules 311
Simple Mail Transfer Protocol (SMTP) 1
Simulator parameter 6
single sign-on (SSO) 293–294, 301–303
SIP. See Session Initiation Protocol
SipTcpListeningPort parameter 11
SipTlsListeningPort parameter 11
SIP Uniform Resource Identifier (URI) 24
site failovers. See failovers
transport rules
site resiliency 65–132
client access server (CAS) layer and 88–101
Database Availability Groups (DAGs) 65–88
for transport 101–116
namespaces 88–91
namespace URLs and 91–94
send/receive connectors for 111–112
troubleshooting 116–127
site rollover
predicting client behavior during 96–99
steps for 94
SKU (stock keeping unit) 205–216
smart cards 147
evaluating 142–144
virtual 144
smarthosts 102, 106–107, 115
S/MIME. See Secure/Multipurpose Internet Mail Extensions (S/MIME)
SMTP. See Simple Mail Transfer Protocol
SMTP domain name 92
SMTP protocol site resiliency for 101–116
SMTP servers 120
load balancing 104
MX records and 103–107
Snooper 54
spam filtering 102, 106
Specify Cryptographic Mode configuration dialog box
164–165
split-brain conditions 66, 68, 69, 86
SQL Server 299
SSL certificates 5, 22, 43, 54
creating replacement 46–47
enabling for UM use 47–48
management of 46
viewing installed 43–45
standalone server farms 298
Standard Edition 75
Start-DatabaseAvailabilityGroup 71
Start-ManagedFolderAssistant 241
Start-MigrationBatch 343
STARTTLS verb 155, 325
Start-Transcript 123
Status parameter 6
Stop-DatabaseAvailabilityGroup 71, 94, 123
Stop-Transcript 123
storage area network (SAN) 203–204
Storage Calculator 78
sts.domain.com 296
subject alternative name (SAN) certificate 43
switchover events 71
Synchronized Identity 293
SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9} 181–182
T
TCP 64327 85
TCP layer 97
TCP port changing 85
TCP port 25 122
TCP port 443 295, 301, 330, 349
TCP port 2525 122
Telephone Extension dial plan 23
telnet 120, 121
telnet remote_IP_address port 120
Test- cmdlets 182
Test DLP Policy With Policy Tips 228
Test-FederationTrust 348
Testing Without Policy Tips 225
Test-IRMConfiguration 170–171, 195
text extraction engine 222, 227
Text-to-Speech (TTS) engine 3–4, 12
third-party migration services 339
time.windows.com 187
TlsAuthLevel parameter 158–160
TlsCertificateName parameter 158
TlsDomain parameter 158, 159
TLSReceiveDomainSecureList 156
TLSSendDomainSecureList 156
tranport protection rules creating 169–172
transaction logs 125
transport decryption 174
TransportDecryptionSetting 174, 175
Transport Layer Security (TLS) 155–162
comfiguration of mutual TLS with Domain Secure
156–158
opportunistic 155
sending errors 160
transport rules 161–162
with send connectors 158–160
transport mail queue database 114
transport pipeline 175–176
transport-related configuration 123
transport rules 161–162, 222–232
exceptions for 269
for compliance requirements 268–270
371
transport services
for ethical walls 260–263
message classifications and 267
version numbers and 269
transport services 121
decryption 174–176
frontend 113–114
MX records and 102–107
resubmission and reroute queues 107–111
site resiliency for 101–116
steps for transport rollover 112–114
troubleshooting 122, 347–348
troubleshooting
Certificate Revocation List access and placement
189–192
client connectivity 119
connectors 120–121
cross-forest availability 350
datacenter activation 123
digital certificates 187–189
DirSync 349
federation trusts 348–349
Information Rights Management (IRM) 194–195
mail flow 119–123, 347–348
mutual Transport Layer Security 43–48
organization relationships 348–349
private keys 192–194
proxy and redirection issues 118–119
Quality of Service (QoS) 52–53
quorum issues 117–118
RBAC 195–196
security 186–198
SIP communications 53–54
site resiliency 116–127
SSO/AD FS 349
transport-related configuration 123
transport service 122
transport services 347–348
Unified Messaging 42–55
Trusted Platform Module (TPM) 139–141
TXT records 308
UM IP Gateway tab 8
UM role 343
UMStartupMode parameter 11
Unified Communications 2–3
Unified Communications Certificate 43
Unified Communications Managed API (UCMA) 51
unified global address list 283
Unified Messaging (UM)
configuration of 4–27
auto attendant 12–18
call answering rules 18–21
IP gateway 4–9
UM call router 9–10
configuring QoS for 52
dial plans creating 23–26
enabling SSL certificates for 47–48
features of 1, 2–3
high availability 21–23
installation 3–4
language packs 38–41
installation of 38–39, 40
removing 40
viewing installed 39
mailbox policy, configuring 35–38, 41
management of 27–42
assigning dial plan to user 27–28
enabling and disabling features 29–32
moving users between dial plans 28
migration 55–61
monitoring calls and call statistics 48–51
troubleshooting 42–55
uniform resource locators (URLs)
namespace, configuring 91–94
Update-MailboxDatabaseCopy 71
USB smart card readers 143
user accounts 293–294
user population location of 80–81
user principal name (UPN) 281, 302
user's licenses 207
U
VIP Editor 136–137, 137
virtual smart cards 144
virus filtering 102, 106
voice mail 2–3
Call Answering Rules 2–3
message transcription 2–3
missed call notifications 2–3
UM call router
call redirection via 10
configuration of 9–10
ports and addresses used by 10–11
372
V
XML files
Outlook Voice Access 3–4
play on phone feature 3–4
protected 2–3, 33–35, 41
Voice over IP (VoIP) 10, 53
W
WAN failure modeling 79
WAP/AD FS proxy servers 295, 295–296, 297
Web Application Proxy (WAP) 294
configuration 300–301
web proxies 309
Wide Area Network (WAN) 22
wildcard certificates 298
Windows Firewall 53
Windows Internal Database 299
Windows Performance Console
viewing active calls in 51
Windows Server 2008 R2 75, 76, 77, 82, 85
BitLocker and 141
Windows Server 2012 75, 76, 82, 85
Windows Server 2012 R2 75, 82, 85, 117
WitnessDirectory parameter 74
Witness.log 87
witness server 73–75, 76, 77, 117
boot time of 70
WitnessServer parameter 74
X
XML files 184–185
373
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