overview of typical windows server roles

overview of typical windows server roles
OVERVIEW OF TYPICAL WINDOWS SERVER ROLES
Before you start
Objectives: learn about common server roles which can be used in Windows environment.
Prerequisites: no prerequisites.
Key terms: network, server, proxy, services, web, segment, firewall, internet, applications,
gateway, router
What are Server Roles
Role is a set of features and services that are required to perform a specific function on the
server and in that way in our environment. Software components in Windows Server system
are separated, and that allows us to install only certain portions of the operating system.
Those portions can be grouped into, what we call, roles. Different roles will then have
different role services. Role services are specific programs that provide the function of the
role. Together with roles we can also use different features of the operating system as an
add-on to roles. Feature programs are not directly related to a role. They often add
functionality to the whole server. Examples of roles include DNS server, DHCP server, File
Server, and Print Server. Some roles, like DNS, have a single role service. Other roles, like
Print Server, have multiple role services such as the LPD Service for Unix printing and
Internet Printing. Features include management tools, communication protocols or clients,
and clustering support.
Network Services
The first role that we will talk about is providing services. In this role our server provides
services to clients on the network. These services include Active Directory, File, Print,
DNS, DHCP and Web (IIS) services. If we can save a file to a server or if we can send a
print job to a server, then that server is running some software that is enabling us to do
those actions on the server. The same thing is if we have a web server. We request a web
page and the server returns the requested web page. If we use Active Directory services, our
computer will act as a Domain Controller (DC). All those scenarios are very common in
server environments.
Active Directory (AD) is a database that stores information about network users, computers
and printers. It helps administrators to mange all those resources, and it is required for
Exchange Server implementation and Domain Group Policy. We should differentiate Active
Directory Domain Services (ADDS) and Active Directory Certificate Services (ADCS). We
can use ADCS to create manage public key certificates. Administrators can use ADCS to
bind the identity of a person, device or service to a specific private key.
DNS is used to map IP addresses to logical names. With Server 2008 we also have support
for IPv6 addresses. DHCP (Dynamic Host Configuration Protocol) service can be used to
provide IP configuration information for hosts on our network including local IP address,
default gateway, DNS server, etc. Print services allows us to manage printers on servers and
to publish printers in Active Directory.
With File Services we can manage network file sharing. We can use Distributed File
Service to store copies of shared folders on multiple servers. We can also manage quotas for
users by using File Server Resource Manager (FSRM). We can also provide access to files
by using NFS protocol which is often used on Linux machines.
Starting from Windows Server 2008 version, we also have Windows SharePoint services,
Network Access Protection, improved Terminal Services, and Windows Deployment
Services (WDS). Windows Sharepoint provides collaboration tools. Network Access
Protection can be used to restrict access on our network for certain computers which are not
compliant with our security policies. Terminal Services can be used to access server
desktop over network or to run applications on terminal server. Windows Deployment
Service can be used to deploy and install various Windows operating systems over
network.
Active Directory (AD) Server Roles
There are several commonly used Active Driectory Server Roles:
·
Active Directory Domain Services (AD DS) - AD DS is a distributed database that
stores and manages information about network resources, such as users, computers, and
printers. This helps administrators to securely manage information, resource sharing and
collaboration between users.
·
Active Directory Lightweight Directory Service (AD LDS) - AD LDS, formerly known
as Active Directory Application Mode (ADAM), is an LDAP directory service that can
be used to create a directory store (database) for use by directory-enabled applications. It
is similar to Active Directory Domain Services (AD DS), but is customizable and can be
much smaller than an AD DS database.
·
Active Directory Federation Services (AD FS) - AD FS is a feature which enables
secure access to web applications outside of a user's home domain or forest. It provides
Web Single-Sign-On (SSO) technologies to authenticate a user to multiple Web
applications using a single user account. It securely federates (shares) user identities and
access rights in the form of digital claims between partner organizations.
·
Active Directory Rights Management Service (AD RMS) - AD RMS is a feature which
safeguards digital information from unauthorized use. It can define exactly how a
recipient can use information, specifying who can open, modify, print, forward, and/or
take other actions. It allows organizations to create custom usage rights templates (such
as "Confidential - Read Only") that can be applied directly to information such as
financial reports, e-mail messages, etc.
·
Active Directory Certificate Services (AD CS) - AD CS is an identity and access control
feature that creates and manages public key certificates used in software security
systems. It provides customizable services for creating and managing public key
certificates, and enhances security by binding the identity of a person, device, or service
to a corresponding private key. It includes features that allow us to manage certificate
enrollment and revocation in a variety of scalable environments. AD CS supports digital
signatures, encrypting File System (EFS), Internet Protocol security (IPsec),
Secure/Multipurpose
Internet
Mail
Extensions
(S/MIME),
Secure
Socket
Layer/Transport Layer Security (SSL/TLS), Secure wireless networks, Smart card
logon, and Virtual Private Networks (VPN).
Not all roles are supported on all versions of Windows Server OS. For example, when it
comes to Windows Server 2008, AD FS is only supported in DataCenter or Enterprise
editions of Windows Server 2008.
Applications Server
When the server is configured as application server, the server will provide certain network
applications that can be accessed by users. For example, the server can have a database
software installed that the users on the network can use to store or query data. When we talk
about the client/server model, database servers can be programs that provide database
services or they can be computers that are dedicated to running database programs.
Another example of applications on our server would be web-based applications. Web
applications are not static web pages. Web application can be any web site that provides
dynamic data or services to users. For example, web applications are web calendars, online
spreadsheets, chat rooms, online CRM software, etc. There are different technologies which
can be used to write web applications, but some of the most popular ones are PHP and
ASP.NET.
Roles that we mentioned up to now are designed to provide services to users. However,
there other roles which are related to network infrastructure. Those roles are the Gateway or
Router, Bridge, Firewall or Proxy.
Gateway or Router
Technically, gateway and router are two different things. However, often the Gateway and
Router are sometimes used interchangeably. That's because we often implement a Gateway
when we implement a Router and vice versa. Gateways and Routers are similar in that they
connect two distinct logical networks. To set the server to function as Gateway or Router,
the server has to have two (or more) network interfaces installed. One network interface is
connected to one network segment and the second interface is connected to another network
segment. This alone will not make our server to route packets between those two network
segments. We also have to have routing software installed. Operating systems like
Windows, Linux and NetWare have this software. Hosts on different network segments will
have different logical addresses (IPs) assigned. Our server (now router) will use IP
addresses to route packets from one segment to another. If host on one network segment
needs to send some data to a host on another network segment, it will first send data to a
Default gateway. Default gateway will know on which network segment the destination
host resides, so it will route data to that network segment. We can actually configure
multiple routers to cover many different networks. That's how the Internet actually works.
Bridge
This role is not used often any more, but it was common in the old days. As we said, with
Router we connect two different logical network segments. Now, with Bridge we connect to
different physical network segments. With Bridge, those two physical networks are still one
logical network segment. Bridge uses MAC (physical) addresses to isolate traffic from one
physical network segment from another. So, the Bridge memorizes which host is on which
physical network segment using the Mac address.
Firewall
Firewall role is often implemented on servers. The Firewall separates our internal computer
network from the public network, which is usually the Internet. We want to allow some
traffic from the Internet, but we also want to block some traffic from the Internet. Most
operating systems have firewall software in them, like Linux and Windows. By using
Firewall we can configure set of rules in which we define what and which type of network
traffic is allowed to enter (or exit) our private network and which is not allowed. So, we can
configure inbound and outbound rules. All traffic going between our local network inside
and the public network outside has to go through the Firewall. The Firewall analyzes all that
trafficking and based on the defined rules, decides to allow or deny specific traffic.
Proxy
Most operating systems also have a proxy feature which can be enabled. With proxy server
we separate and hide our private network from the Internet, and we also have a degree of
control which resources on the Internet are being accessed. A server running as a firewall
can also run as a proxy or a separate proxy server can be set up. All hosts on the network
are connected to our proxy server. If some host on our private network wants to go the
Internet, it has to go trough our proxy server. The proxy server takes a look at all requests
and decides to allow or deny the request based on the configured rules. If the request is
allowed, the servers send it out on the Internet and retrieve the resource requested (or its
gets it from its cache). Then it forwards the results back to the original workstation. When
we use a proxy server the address of the proxy server is the only address available to the
public network.
Common Features
As we mentioned earlier, we can also use many features to improve services on our server
machine. For example, we can use BitLocker. We can also set up Remote Assistance
service, SMTP, Telnet server or Telnet client feature. We also have Failover Clustering,
Network Load Balancing (NLB), WINS, Windows Backup and Powershell, Windows
Backup and Powershell.
BitLocker is used to encrypt the entire hard disk on the server and in that way protect data
on it. Remote Assistance is used to offer assistance to users on their computers and to
correct problems over network. Simple Mail Transfer Protocol (SMTP) is used to transfer email between systems and clients. For example, we can add SMTP feature to add e-mail
support to IIS. With Telnet feature we can use a command line to manage remote servers.
Telnet Server allows us to accept incoming connections, while Telnet Client allows us to
initiate connections. Failover Clustering is used to increase the fault tolerance of network
servers by sharing storage resources. In that way if one server fails, the available server will
respond to the requests. Network Load Balancing feature is used to disperse workload
between multiple servers to optimize performance and response time. This also provides
fault tolerance. WINS server is used to map NetBIOS names and IP addresses. WINS
database is used to resolve NetBIOS names. It is only used if we need to support legacy
clients which can't use DNS for name resolution (DNS replaced WINS). Windows Server
Backup can be used to backup and recover content from Windows Server machine.
Powershell is a command line scripting program which can be used to manage Windows
Server.
Server 2003 vs Server 2008
To manage all those roles and features, in Windows Server 2003 OS we often used
Computer Management MMC console. In Server 2008 we don't have Computer
Management, and in place of that we have a new MMC console called Server Manager.
Server Manager console allows us to add or remove roles, customize roles and work with
additional features. Installation of roles in Server 2003 was similar to using Add/Remove
Windows Components in Control Panel. In Windows Server 2008 the only way to add roles
is trough Server Manager console.
Server Core Editions
Server core is a minimal server installation option available on Windows Server 2008 and
newer Windows Server versions. It has limited GUI support, so most tasks are performed
from a command prompt. The thing is, server core will only be able to run limited set of
server roles, so be sure to check the documentation for the Windows Server version you are
using or run oclist to see a list of roles, role services, and features that can be installed on
server core. Run start /w ocsetup to add server roles to the server core system. Switches for
the role or service must be typed exactly as they are listed, and role names are casesensitive.
Source : http://www.utilizewindows.com/server/basics/354-overview-of-typicalwindows-server-roles
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