Point-to-Point Protocol (PPP)
Overview
Overview
STREAMware PPP is a STREAMS-based computer networking facility that provides for the transmission and
reception of IP packets over serial lines. As such,
STREAMware PPP provides for the use of TCP/IP networking applications such as rlogin and telnet over
serial lines.
STREAMware PPP is an implementation of the Point-toPoint Protocol (PPP) as defined in the following Internet
standards: RFC 1144, RFC 1172, RFC 1332, RFC 1334,
RFC 1471, RFC 1473, and RFC 1548.
Use PPP when an Ethernet or token ring connection
between the local host and another location is not possible but a serial line connection is. PPP can be used to
connect the local host to another host via a single,
physical serial line connection between serial ports or
over longer distances using telephone lines and modems. A computer that is running PPP over one or more
serial lines and that is also connected to a computer
network (such as an Ethernet) can serve as a communication gateway between computers on the network and
the computers at the far ends of the serial lines.
This chapter describes:
•
how STREAMware PPP works
•
STREAMware PPP features
•
overview of PPP configurations
STREAMware TCP Administrator's Guide
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Point-to-Point Protocol (PPP)
Overview
•
PPP negotiation
•
compatibility with other PPP implementations
•
complex PPP scenarios
•
MIB support logging
•
configuring PPP links
•
administering PPP
•
troubleshooting PPP
Also available for serial line communication instead of
PPP is SLIP. See Chapter 4, “Using the Serial Line Internet Protocol (SLIP),” for more information on SLIP.
STREAMware TCP supports only asynchronous communications.
Terminology used in this chapter:
line
as in serial line — the physical medium over which
data flows
link
as in PPP link — the virtual connection between two
machines over which data flows
interface
as in PPP interface — the abstract entity to which
the IP driver routes datagrams
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Point-to-Point Protocol (PPP)
How STREAMware PPP Works
How STREAMware PPP
Works
STREAMware PPP provides for the use of TCP/IP network applications over serial lines by linking serial lines
to the IP protocol driver through a series of drivers and
modules called the PPP STREAMS stack. In addition,
the drivers and modules implement various Internet
standards that govern the transmission of data over
serial lines attached to the PPP STREAMS stack.
The PPP STREAMS stack consists of:
Components
•
packet filter module, ipf(7)
•
PPP driver, ppp(7)
•
asynchronous HDLC protocol module, asyhdlc(7)
The most important component in the stack is the PPP
driver that handles the framing of the IP packets for
their transmission and reception over serial lines. Another important function of this driver is PPP negotiation with the remote host that ensures a sound
connection before any transmission of application data.
(For more information on these components, see the
listed manual page found in the STREAMware TCP for
MP-RAS Administrator's Reference Guide.)
PPP Links
Each connection over a serial line linked to the IP driver
through the PPP STREAMS stack is a PPP link. Each
PPP link requires a unique network interface between
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Point-to-Point Protocol (PPP)
How STREAMware PPP Works
the IP driver and the PPP driver called a PPP network
interface. What makes each PPP network interface
unique is the unique remote and local IP addresses.
A network application on the local host uses a PPP link
by specifying the remote host IP address of an existing
PPP network interface. For example:
telnet 132.147.118.7
(The application can also specify a remote host name if
name resolution is available.) When the IP driver receives a packet whose destination IP address is associated with a PPP network interface, the IP driver routes
that packet to the PPP driver via the network interface;
the PPP driver, in turn, puts the packet out on the serial
line associated with that PPP network interface. When
the PPP driver receives a packet over the serial line, it
passes it to the IP driver via the unique network interface associated with the link over which the packet
came.
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Point-to-Point Protocol (PPP)
How STREAMware PPP Works
Before a networking application can use PPP:
•
the system administrator must create the
/etc/inet/ppphosts file containing one or more PPP
link configurations. See “PPP Link Configurations”
(page 3-13) for a description of the 4 types of PPP
link configurations.
•
the PPP daemon (pppd) must read the link configurations. The PPP daemon reads the link configurations each time STREAMware TCP starts up or
when pppd receives a SIGHUP signal. See
“Signaling the PPP Daemon” (page 3-76) for information on signaling the daemon.
Typically, once the above is completed, a network application can use a PPP link transparent to the network
application user. The application user need only specify
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Point-to-Point Protocol (PPP)
How STREAMware PPP Works
an IP address or host name. There are some PPP links,
however, for which the user might be required to execute a PPP command to establish the PPP link before
executing the network application. For an explanation
of this type of link, see “Manual Outgoing Link Characteristics” (page 3-16).
Multiple applications (or multiple instances of the same
application) on a local host can communicate with the
same remote host using the same PPP link. Use of the
same PPP link requires only that the applications use
the same IP remote address. By using different IP addresses to specify the same remote host, two applications can also use individual PPP links to that host,
provided a separate serial line is available for each address and each address has a unique PPP network interface.
Once a PPP link is established, it remains active until
the administrator marks the interface down or the idle
timer expires. Use ifconfig to mark an interface down.
The idle timer is set in the PPP link configuration.
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Point-to-Point Protocol (PPP)
STREAMware PPP Features
STREAMware PPP Features
This release of STREAMware PPP provides:
•
Support for up to 64, simultaneous PPP links.
•
Support for PPP communications initiated on a local
host and PPP communications initiated from a remote host.
•
Establishment of a PPP link over a serial line dedicated for use only by a PPP link or over dynamically
acquired serial lines shared with the CU and UUCP
facilities.
•
Dynamic IP addressing. STREAMware PPP can be
configured for the dynamic allocation of IP addresses during PPP negotiation.
•
IP address pooling. For incoming links, the local
host can assign IP addresses from a predefined pool
of IP address pairs.
•
Dynamic PPP link configuration, which negates the
need to relink the kernel or stop/restart TCP/IP to
make PPP link configuration changes. Further information is contained in “Signaling the PPP
Daemon” (page 3-76).
•
Two-level priority packet handling. The PPP driver
implements a two-level priority scheme in the
handling of packets. Given highest priority over
other packets, but equal priority among themselves,
are rlogin, telnet, and ftp packets. All other packets
are handled as a lower priority.
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STREAMware PPP Features
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•
Packet filtering. STREAMware PPP provides a
mechanism for specifying what types of IP packets
(for example, those carrying FTP data versus those
carrying RIP data) will pass through a PPP network
interface, bring up a PPP network interface, or reset
the idle timer of a PPP network interface. For more
information, see “PPP Packet Filtering” (page 3-18)
•
PPP server and PPP gateway services. See “PPP
Gateway” (page 3-22) and “Complex PPP Connection Scenarios” (page 3-35) for more information.
•
Negotiation of link and IP parameters. For more
information on negotiation, see “PPP Negotiation”
(page 3-26).
•
Authentication of the local host by the remote and of
the remote host by the local. STREAMware PPP
supports 2 types of authentication: PAP and CHAP.
For more information on authentication, see “PPP
Authentication Methods” (page 3-17).
•
Access to STREAMware PPP debugging information. STREAMware PPP logs debugging information
about its own activity through syslog(3) and the
pppstat command. The amount of information
logged to syslog is configurable. Information regarding PPP's use of UUCP services is also available by
activating the logging of this information to the console. For details on debugging information, see
pppstat(1M) in the STREAMware TCP for MP-RAS
Administrator's Reference Guide. In this chapter, see
“Logging PPP Information” (page 3-41).
•
PPP MIB support. STREAMware PPP responds to
queries from the SNMP daemon for information regarding the objects in 2 PPP MIBs. For more information, see “PPP MIB Support” (page 3-41).
STREAMware TCP Administrator's Guide
Point-to-Point Protocol (PPP)
STREAMware PPP Features
Uniqueness of PPP
Network Interfaces
Normally, the building or rebuilding of any network
interface requires restarting the network software that
uses that interface. Since STREAMware PPP requires a
separate interface for each PPP link, the addition of a
PPP link under the normal requirements would necessitate restarting the network software. STREAMware PPP
has been implemented to eliminate this cumbersome
step when adding or changing a PPP link by building
PPP network interfaces dynamically. Adding or changing
PPP links only requires altering PPP link configuration
files and having pppd reread those files.
The advantage of building network interfaces dynamically is the ability to dynamically assign IP addresses to
a PPP link. STREAMware PPP does not build all PPP
network interfaces in the same way. In STREAMware
PPP, pppd builds the network interfaces. The daemon
uses the information it reads in the PPP link configurations for directions on how and when to build PPP network interfaces. STREAMware PPP has four types of
PPP link configurations which are described in “PPP
Link Configurations” (page 3-13).
For the dedicated and the dynamic outgoing types of
link configurations, pppd builds the PPP network interface when pppd is started or when it receives a
SIGHUP. These configurations require that the IP addresses which define the network interface must be
specified in the link configuration and must be used for
that link.
For the dynamic incoming and the manual outgoing
types of link configurations, pppd builds the PPP network interface when the link is needed. Because of this
delay, the assignment of IP addresses to define the net-
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Point-to-Point Protocol (PPP)
STREAMware PPP Features
work interface can take place during PPP negotiation.
See “PPP Negotiation” (page 3-26).
For a complete description of how and when pppd
builds network interfaces, see the pppd(1M) manual
page in the STREAMware TCP for MP-RAS Administrator's Reference Guide.
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Point-to-Point Protocol (PPP)
Overview of PPP Configuration
Overview of PPP
Configuration
PPP uses the following four configuration files.
PPP Configuration
Files
/etc/inet/ppphosts
This is the main PPP configuration file. Each PPP link
must have a separate entry in this file; pppd reads this
file as part of its startup procedure. The daemon can
also be signaled to reread this file. (See “Signaling the
PPP Daemon” (page 3-76).) A sample ppphosts file exists
at /usr/lib/ppp/ppphosts. You can copy this sample file to
create the /etc/inet/ppphosts file.(See the ppphosts(4)
manual page in the STREAMware TCP for MP-RAS Administrator’s Reference Guide.)
/etc/inet/pppauth (optional)
This file is required only if authentication will be required for establishing any PPP links. This can be initiated by either the local host or the remote host. This file
holds the data required for authentication and is read by
pppd during PPP negotiation. See “PPP Authentication
Methods” (page 3-17) and the pppauth(4) manual page
in the STREAMware TCP for MP-RAS Administrator's
Reference Guide. A sample pppauth file exists at
/usr/lib/ppp/pppauth. You can copy this sample file to
create the /etc/inet/pppauth file.
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Overview of PPP Configuration
/etc/inet/pppfilter (optional)
This is the file for PPP packet filter specifications. It is
required only if packet filtering will be required for one
or more PPP links. Packet filtering can be specified on a
per-link basis. pppd reads the packet filter file as part of
its startup procedure. The daemon can also be signaled
to reread this file; see “Signaling the PPP Daemon”
(page 3-76). See “PPP Packet Filtering” (page 3-18) and
the packetfilter(4) manual page in the STREAMware
TCP for MP-RAS Administrator's Reference Guide. A
sample pppfilter file exists at /usr/lib/ppp/pppfilter. You
can copy this sample file to create the /etc/inet/pppfilter
file.
/etc/inet/ppppool (optional)
This file is required only if IP addresses for dynamic
incoming PPP links will be assigned from a pool at link
bringup time. See “Configuring a Dynamic Incoming
PPP Link” (page 3-49) for more information on this
option and the ppppool(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference
Guide. A sample ppppool file exists at /usr/lib/ppp/ppppool.
You can copy this sample file to create the
/etc/inet/ppppool file.
STREAMware PPP uses the following configuration
files indirectly:
/etc/inet/hosts
This file provides for the mapping of host names to
host IP addresses. Your system can use /etc/inet/hosts,
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Overview of PPP Configuration
Domain Name Service (DNS), or the Network Information Service (NIS) for name to address mapping. If
users enter names when executing applications that
require a PPP link or if host names appear in any PPP
configuration files, your system must provide one of the
above methods. If the etc/inet/hosts file will provide the
mapping, this file must contain an entry for any host
name which will be mapped.
/etc /uucp/Systems, /etc /uucp/Devices, /etc /uucp/Dialers
These three files are UUCP systems files. Dynamic outgoing and manual outgoing PPP links require entries in
these files for PPP to be able to use UUCP facilities for
these links. This dependency is described in “UUCP
Facility Use for Outgoing PPP Links” (page 3-21).
PPP Link
Configurations
pppd can only build PPP links if PPP link configurations exist. Every link is based on a link configuration,
but in some cases more than one link may be based on a
single link configuration (for example, dynamic incoming links using address pooling). A link configuration
consists, at minimum, of an entry in /etc/inet/ppphosts.
Depending on the type of link configuration used for
that entry, entries will be required in the files:
•
/etc/inet/pppauth
•
/etc/inet/pppfilter
•
/etc/inet/ppppool
See “PPP Configuration Files” (page 3-11) for a description of these configuration files and others used by
STREAMware PPP.
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Point-to-Point Protocol (PPP)
Overview of PPP Configuration
There are four types of link configurations described in
the following sections. Each type has different optimal
uses and characteristics. The number and content of
PPP link configurations on a system depends on the
types of PPP communications anticipated for the system.
The following link types are supported:
•
dedicated (page 3-15)
•
dynamic incoming (page 3-15)
•
dynamic outgoing (page 3-16)
•
manual outgoing (page 3-16)
PPP Link Reference Table
Following is a quick reference table of PPP link configurations.
3-14
Link Type
Line
Initiation
dedicated
dedicated
local or remote local
dynamic incoming
dynamic
shared
remote
local or remote
dynamic outgoing
dynamic
shared
local
local
manual outgo- dynamic
ing
shared
local
local or remote
STREAMware TCP Administrator's Guide
IP Address
Assigned By
Point-to-Point Protocol (PPP)
Overview of PPP Configuration
Dedicated Link Characteristics
Use the dedicated link configuration when you use a
dedicated serial line to connect with the remote host.
This type of configuration is used with a serial line that
is reserved exclusively for a single connection. Examples of such lines include a leased line between buildings or a serial cable connecting two machines.
Note: If the remote host must assign the IP addresses,
you must use one of the dynamic type configurations.
The dedicated link configuration:
•
requires a serial line dedicated to a single PPP link
with a single remote host
•
allows for initiation by either the local or remote
host
•
requires that IP addresses identifying the local and
remote hosts must be specified by the local host and
accepted by the remote host
Incoming Link Characteristics
Use a dynamic incoming link configuration when you
need to accept PPP connection requests from remote
hosts over dynamically acquired serial lines. This type
of link:
•
requires a dynamically acquired, shared serial line
•
requires initiation by the remote host through a
ttymon(1M) type login
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Point-to-Point Protocol (PPP)
Overview of PPP Configuration
•
allows IP addresses identifying the local and remote
hosts to be specified by either the local host or the
remote host
Dynamic Outgoing Link Characteristics
Use this type of link when you need to initiate a PPP
connection with a remote host over a dynamically acquired serial line, and the local host can assign both IP
addresses. This type of link:
•
requires a dynamically acquired, shared serial line
•
requires initiation by the local host; bringup of the
link is initiated by the presence of an outgoing IP
packet for the remote host IP address
•
requires that IP addresses identifying the local and
remote hosts must be specified by the local host and
accepted by the remote host
Manual Outgoing Link Characteristics
Use this link type when you need to initiate a PPP connection with a remote host over a dynamically acquired
serial line and the remote host must be able to assign
one or both of the IP addresses. This link type:
3-16
•
requires a dynamically acquired, shared serial line
•
requires initiation by the local host; bringup of the
link is initiated by the execution of the command
pppattach (For more information, see pppattach(1M) in the STREAMware TCP for MP-RAS Administrator's Reference Guide.).
STREAMware TCP Administrator's Guide
Point-to-Point Protocol (PPP)
Overview of PPP Configuration
•
PPP Authentication
Methods
allows IP addresses identifying the local and remote
hosts to be specified by either the local host or the
remote host.
PPP authentication provides that a host, before establishing a PPP connection, can require that the other host
uniquely identify itself using pre-arranged, secure data.
STREAMware PPP supports two methods of authentication: Password Authentication Protocol (PAP) and
Challenge-Handshake Authentication Protocol
(CHAP).
Authentication and the protocol to be used is selectable
on a per-link basis within PPP link configurations.
Therefore, some PPP links can require authentication
and others may not; some PPP links can use PAP and
others may use CHAP.
The default status of any PPP link is to require NO
authentication of the remote host. If a PPP link is to
require authentication, the link configuration entry in
the /etc/inet/ppphosts file must include one or more of the
authentication parameters. These parameters are:
auth
must be set to pap or chap to require authentication
and select the protocol which the remote system
must use
authtmout
determines the amount of time in minutes that the
local host PPP waits for the remote host PPP to
authenticate itself. This parameter is optional; it defaults to 1 minute.
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Point-to-Point Protocol (PPP)
Overview of PPP Configuration
name
indicates the entry to use from the /etc/inet/pppauth
file (see below) for local host id lookups. If there is a
default entry in the /etc/inet/pppauth file, this is optional.
The pre-arranged, secure data used for authentication
consists of two fields stored in the file /etc/inet/pppauth:
•
name
•
password
See the pppauth(4) manual page in the STREAMware
TCP for MP-RAS Administrator's Reference Guide for a
description of these fields, a description and example of
the format of this file, and a comparison of the PAP and
CHAP methods of authentication.
For a detailed description of the PAP and CHAP protocols, see RFC 1334.
PPP Packet Filtering
Packet filtering permits control of the traffic through a
PPP network interface based on the contents of the
packets passed to the interface. Packet filter control is
provided for these interface functions:
bring up
By default, any type of packet passed to a dedicated
or dynamic outgoing PPP interface will cause the interface to be brought up if it is down. Packet filtering can specify which types of packets bring up a
PPP interface.
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Overview of PPP Configuration
pass
By default, any packet passed to an interface is allowed to pass through that interface. Packet filtering
can specify which types of packets can pass through
a PPP interface.
keep up
By default, any packet passed to an interface will reset the idle timer for that interface. (Expiration of the
idle timer will cause the interface to be automatically
brought down.) Packet filtering can specify which
types of packets can reset the idle timer for a PPP interface.
Packets can be qualified or disqualified for:
•
transport level protocol type (that is, tcp, udp, icmp)
•
IP destination or source fields (IP address or host
name)
•
destination or source port field in TCP or UDP
packets
•
packet length
•
IP packet type (that is, broadcast or multicast)
Packet filtering is specified on a per-link basis. To specify a packet filter for a PPP link:
•
include the parameter filter=tag in the
/etc/inet/ppphosts entry for the link
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Point-to-Point Protocol (PPP)
Overview of PPP Configuration
•
create a filter entry in the file /etc/inet/pppfilter whose
tag field matches the value of tag in the
/etc/inet/ppphosts entry. See the packetfilter(4) manual page in the STREAMware TCP for MP-RAS Administrator's Reference Guide.
Two or more PPP link configurations may specify the
same filter file entry.
If /etc/inet/pppfilter does not exist, then all packets bring
up the interface, all packets pass, and all packets reset
the idle timer.
If /etc/inet/pppfilter exists, pppd assigns a default value
to the filter=parameter for each link, depending on the
type of link. For dynamic incoming, dynamic outgoing,
and manual outgoing links, pppd assigns filter=default. For dedicated links, pppd assigns filter=dedicated.
A sample pppfilter file exists at /usr/lib/ppp/pppfilter. This
sample file includes a filter specification with the tag
default and a filter specification with the tag dedicated.
The dedicated filter specification does nothing. The
default filter specification looks like the sample shown
below and specifies the following:
# tag
Keyword
default
bringup
3-20
•
Does not allow xntpd, rwhod, routed, timed, gated,
and irdd packets to bring up or keep up the link.
•
Does allow all packets to pass the link.
filter
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89 and !icmp[0] == 9\
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Overview of PPP Configuration
and !icmp[0] == 10\
pass\
keepup
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89 and !icmp[0] == 9\
and !icmp[0] == 10
For dynamic outgoing and manual outgoing
type links, we recommend that you copy the
/usr/lib/ppp/pppfilter file with its default filter
specification to /etc/inet/pppfilter. For dynamic outgoing links, the default filter
specification will prevent the packets mentioned above from bringing up the link,
which would cause financially costly dialups
which are not necessary. For manual bringup
links, it will prevent the link from remaining
up when it is no longer being used.
UUCP Facility Use for
Outgoing PPP Links
Dynamic outgoing and manual outgoing PPP links use
the UUCP facilities as the physical media over which
the link is made. These media are usually modems at
the remote host and the local host and the telephone
lines connecting the modems.
An outgoing PPP link may specify the parameter
uucp=name in the configuration file /etc/inet/ppphosts.
name identifies the remote host to which to connect;
there must be an entry in the UUCP file
/usr/lib/uucp/Systems whose site name field is name.
These corresponding entries of name form the link between PPP and UUCP. If uucp=name is not specified,
the remote IP address in /etc/inet/ppphosts is used by
default.
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Establishing such a connection requires UUCP connectability between the local and remote host without
PPP. When an outgoing PPP link is brought up, PPP
requests a UUCP link to the remote host. UUCP must
be able to establish a UUCP link using only UUCP information, such as that found in the files
/usr/lib/uucp/Systems, /usr/lib/uucp/Devices,
and/usr/lib/uucp/Dialers. During UUCP link establishment, characteristics such as baud rate and flow control
are determined by the UUCP information and NOT by
the PPP link configuration. Once UUCP has established
a UUCP link, it informs PPP of the tty to use for that
link. At this point PPP takes over the link, and the local
host, using the PPP link configuration, may renegotiate
link characteristics. It is best to test a UUCP link between the local and remote hosts before trying to run
PPP over the link.
For complete information on configuring a UUCP link,
see “Basic Networking Utilities” in the NCR UNIX
SVR4 MP-RAS Administrator Guide: Command Line Interface.
PPP makes efficient use of UUCP facilities by dynamically disconnecting from the phone line if the idle time
configured for the PPP link using that line expires. If
additional data must be transferred over that link, the
phone line connection is dynamically re-established.
PPP Gateway
3-22
A PPP gateway is a TCP/IP gateway that has one or
more PPP network interfaces. A TCP/IP gateway is a
machine that has been configured to forward IP packets
which are not addressed to itself. If a TCP/IP gateway
has PPP network interfaces, it will forward packets
which are either received over a PPP connection or are
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Overview of PPP Configuration
addressed to a remote system accessible via a PPP interface.
See Chapter 5, “IP Routing,” for how to configure a
TCP/IP gateway.
For a PPP gateway, you might want to use proxy ARP;
see the following section.
Proxy ARP
Proxy ARP solves the problem illustrated in the figure
below (adm0302c). (For those unfamiliar with ARP, see
the arp (7) manual page in the STREAMware TCP for
MP-RAS Administrator's Reference Guide.)
In the following figure, hosts A and C need to communicate, and the only route is through host B. The IP addresses that define the link between hosts A and B use
the same subnet number as the Ethernet (that is,
192.34.54.0) through which hosts B and C communicate.
Therefore, host C believes the IP address 192.34.54.4 to
have an Ethernet connection on the LAN. When the IP
protocol layer of host C receives a packet addressed to
192.34.54.4, host C puts an ARP broadcast on the LAN
asking the host of that IP address to respond with its
Ethernet address. Because host A is not on the LAN,
host C receives no response and believes it cannot
communicate with that IP address.
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The proxy ARP solution to this problem is to put entries
in the ARP mapping table on host B that map the IP
addresses 192.34.54.1 and 192.34.54.4 to the Ethernet
address of host B on the LAN. These are called proxy
ARP entries. Now when host C broadcasts a request for
an Ethernet address for IP address 192.34.54.4, host B
will respond with its Ethernet address. Host C will send
packets for 192.34.54.4 to host B's Ethernet address and
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host B, if configured to forward these packets to host A,
will forward them.
STREAMware PPP provides a link configuration parameter called proxy for automatically putting the
proxy ARP entries in the ARP mapping table. In the
example shown here, host B should include the proxy
parameter in the link configuration for the A<->B link.
When pppd reads this configuration and finds the
proxy parameter, it searches existing (non-ppp and nonloop back) network interfaces on host B to find an IP
address that uses the same subnet number as the IP
addresses of link A<->B. If it finds such a case, it retrieves the Ethernet address for the network interface. It
then inserts entries in host B's ARP mapping table that
map the IP addresses for link A<->B to the Ethernet
address it found.
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Point-to-Point Protocol (PPP)
PPP Negotiation
PPP Negotiation
Before any PPP link is established and data can flow
over the link, pppd must read the parameters in the link
configuration and pass them to the PPP driver. The
driver must negotiate with the remote host using the
link parameters as a starting point. If the local and remote hosts can agree, on the characteristics to use for
the link, the link is established. If the two hosts cannot
agree, the link fails.
For negotiation between the local and remote hosts to
occur, a physical connection must be established between the two hosts. This is the same physical connection that will carry the data of the PPP link when it is
established. At the time of negotiation, the only communication permitted is between the PPP software on
each host. Once PPP negotiation is successful, the PPP
software only manages the link and routes data over the
link; use of the link belongs to the user level software
such as networking applications. Therefore, an
“established” PPP link is one that has successfully
completed PPP negotiation.
There are four stages of PPP negotiation. They are:
1. Internet Control Protocol (ICP)
2. Link Control Parameter (LCP)
3. authentication, and
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PPP Negotiation
4. Internet Protocol Control Parameter (IPCP)
Internet Control
Parameter (ICP)
Link Control
Parameter (LCP)
ICP is an exception to the above description in that
this stage involves negotiation internal to the local
system running STREAMware PPP. No specified
configuration parameters are negotiated here. ICP is
unique to STREAMware.
The PPP driver negotiates link control parameters
with the remote host:
•
maximum receive units
•
asynchronous control character map
•
magic number
•
protocol field compression
•
address-control field compression
•
authentication
For these parameters, the local host may change the
value of a parameter from that specified in its configuration file and accept the value suggested by the
remote host.
Authentication
Internet Protocol
Control Protocol
(IPCP)
Authentication is optional. The PPP driver negotiates PAP or CHAP authentication if either the local
and/or remote side requires it.
The PPP driver negotiates IPCP parameters with the
remote host:
•
Van Jacobson TCP/IP header compression
The local host can change the state of this parameter from that specified in its configura-
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Point-to-Point Protocol (PPP)
PPP Negotiation
tion file and accept the state suggested by
the remote host.
•
IP addresses
IP address negotiation is a little different
from negotiation of the TCP/IP header compression or the LCP-stage negotiated parameters. This is because IP addresses are
significant to both the interface and the link;
the other parameters are only significant to
the link.
IP address negotiation is initiated by the local host on every link by default. Local host
initiation of IP address negotiation can be
turned off by specifying the noipaddr parameter in the link configuration. If IP address negotiation is not initiated by the local
host, it can still be initiated by the remote
host.
Dedicated or dynamic outgoing links
For dedicated or dynamic outgoing links, the
remote host must agree to use the IP addresses (local and remote) assigned by the
local host; if it does not, the local host refuses
the link. If IP address negotiation occurs on
these links, the local host verifies that the
remote is using the same IP addresses. If the
remote is not using the same addresses, the
local host refuses to establish the link. This
alerts the local host administrator of a problem with the link immediately. If IP address
negotiation does not occur and the remote is
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PPP Negotiation
using different addresses, the link will be established but the correct routing of PPP
packets is doubtful. This problem is harder
to identify.
Dynamic incoming links
For dynamic incoming links, the local host
configuration may or may not include local
and remote IP addresses.
•
If the local host configuration does include
these addresses, IP address negotiation has
the same impact as described above for dedicated and dynamic outgoing interfaces.
•
If the local host configuration does not include these addresses, the local host requires
IP address negotiation to occur so the remote
host can furnish IP addresses; otherwise, the
local host refuses the link. It is strongly recommended that the local host initiate IP address negotiation when a dynamic incoming
link does not specify IP addresses.
If the remote host supplies the IP addresses
and either address supplied is a duplicate of
an address already assigned to an interface
on the local system, the dynamic incoming
link will fail.
Manual Bringup Links
For manual bringup links, the local host
configuration could include 0.0.0.0 as the local and remote IP address for the interface. In
that case, the local host requires IP address
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Point-to-Point Protocol (PPP)
PPP Negotiation
negotiation so that the remote host can furnish IP addresses.
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Point-to-Point Protocol (PPP)
Compatibility With Other PPP Implementations
Compatibility With Other PPP
Implementations
The successful establishment of a PPP link requires that
the PPP link configuration of both hosts are compatible.
PPP operation includes parameter negotiation that is
helpful in achieving this compatibility. PPP negotiation,
however, is not always successful in mediating between
the two hosts. This most often occurs when trying to
connect two hosts running PPP from different vendors.
The section “Troubleshooting PPP” (page 3-78) is provided to help you resolve compatibility problems.
Another way to avoid compatibility problems is to
know in advance what parameter settings on each side
are required to achieve compatibility. There are a number of PPP vendors and each has a number of versions
of their software in the field. The following sections
describe required parameters for compatibility with
earlier versions of STREAMware PPP and compatibility
with a few PPP versions from other vendors:
•
Connections with SCO TCP/IP Release 1.2.0 PPP
(page 3-32)
•
Connections with MorningStar PPP 1.3 for SCO
(page 3-32)
•
Connections with Telebit NetBlazer 1.5 (page 3-32)
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Compatibility With Other PPP Implementations
Connections With SCO
TCP/IP Release 1.2.0
PPP
On the STREAMware TCP system, INCLUDE these
parameters in the /etc/inet/ppphosts entry of the PPP link
configuration:
•
rfc1172addr
•
old
On the STREAMware TCP system, EXCLUDE the following parameters from the /etc/inet/ppphosts entry of
the PPP link configuration:
Connections With
MorningStar PPP 1.3
for SCO
Connections With
Telebit NetBlazer 1.5
•
noipaddr
•
novj
•
noprotcomp
•
noaccomp
On the system running MorningStar PPP, do not use
password authentication on both sides at the same time.
MorningStar PPP 1.3 only supports one side password
authentication.
Dialing into a NetBlazer from a UNIX System:
1. Configure the NetBlazer to receive the call from the
UNIX system:
The NetBlazer can be set up as if the UNIX machine
were just another remote dynamic-interface NetBlazer, using the PPP encapsulation protocol in
packet mode.
Configure the NetBlazer as described in Chapter 5
of the NetBlazer Installation Guide, noting particularly
the discussion of the ipdial command. When you
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Compatibility With Other PPP Implementations
are prompted for Name of remote(other) system:, enter the name of the UNIX system. Use PPP
rather than SLIP. Set mtu=1500. Make a note of the
dial-in user password you enter for use by the UNIX
system; you will need to include this password in
the UNIX system's /usr/lib/uucp/System entry that
describes how to dial into this NetBlazer (see next
step).
2. Configure the UNIX system to call the NetBlazer:
In your system's /usr/lib/uucp/Systems file, set the
user name provided by the login portion of the chat
script to the UNIX system name. Make sure you set
the password to the same one you entered for the
dial-in user on the NetBlazer (see step 1, above). You
must include the noipaddr option in the
/etc/inet/ppphosts file because NetBlazer rejects IP address negotiation.
Dialing into a UNIX system from a NetBlazer:
1. Configure the UNIX system to receive the call from
NetBlazer:
Include the noipaddr option in the /etc/inet/ppphosts
file because NetBlazer 1.5 rejects IP address negotiation.
2. Configure the NetBlazer to call the UNIX system:
Add the following entry to the NetBlazer's
CHAT.TXT file:
# for connecting to a STREAMware UNIX machine.
:unix
s1,20,30,2,\n\r
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Compatibility With Other PPP Implementations
e2,20,30,3,in: e3,3,4,4,$6%~&
u4,5,100,5
s5,5,100,6,\n\r
e6,20,30,7,word:
e7,3,8,8,$6%~&
p8,5,100,9
s9,5,100,99,\n\r
s30,20,30,31,\n\r
e31,20,30,32,in:
e32,3,33,33,$6%~&
u33,5,100,34
s34,5,100,35,\n\r
e35,20,100,36,word:
e36,3,37,37,$6%~&
p37,5,100,38
s38,5,100,99,\n\r
r99,0
Reboot the NetBlazer to effect any changes to the
CHAT.TXT file. When you configure the NetBlazer's
dynamic interface to call the UNIX system (as described
in "Configure the NetBlazer to receive the call from the
UNIX system", above), specify unix for the chat script
instead of the default ics.
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Complex PPP Connection Scenarios
Complex PPP Connection
Scenarios
Many networking scenarios use PPP to connect two
hosts over a dedicated line or via modems. While these
scenarios require some effort to achieve a successful
connection, they are simple in that they just involve
configuration of one connection. This section provides a
description of two more complex scenarios that require
multiple connections, to resolve the scenario's networking needs.
Internet Access via PPP Gateway
The first complex connection scenario, Internet access
via a PPP gateway, is illustrated by the following diagram.
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Point-to-Point Protocol (PPP)
Complex PPP Connection Scenarios
Host A needs to access the Internet but has no direct
access. To gain Internet access, host A must use PPP to
connect to host B. This scenario requires that:
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•
a successful PPP link be established between host A
and host B.
•
host B be configured as a PPP gateway (see “PPP
Gateway” (page 3-22) ) .
STREAMware TCP Administrator's Guide
Point-to-Point Protocol (PPP)
Complex PPP Connection Scenarios
•
host B may need to have proxy ARP entries to enable other hosts to send packets to host A (see
“Proxy ARP” (page 3-23) .
•
host A have a default route in its IP routing table
that points to the PPP interface associated with the
PPP link to host B. To add such a default route, you
can use the command:
route add default remote_IP_address
remote_IP_address is the remote IP address for the
PPP link to host B.
PPP Server Scenario
The second complex connection scenario, connecting
through a PPP server, is illustrated by the following
diagram.
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Complex PPP Connection Scenarios
Here, a single host acts as a PPP server. Multiple hosts
connect to this server using PPP, and the server provides services (such as Internet access) to these hosts
over the PPP connections. There are two special configuration issues for a PPP server:
•
the PPP server must be configured as a PPP gateway
(see “PPP Gateway” (page 3-22) )
•
the PPP server must be represented by a unique IP
address to each client.
A configuration decision is whether this address (and
the unique IP address by which the server will know
the client) will be assigned by the server or by each
client.
Note: The following configuration requirements apply
only to the server configuration. Since the clients may
be running a non-STREAMware PPP implementation,
no assumptions are made about the clients' configurations.
Server assigns addresses
This requires the following server configuration:
•
The server must have a login entry in its
/etc/inet/ppphosts file (that is, a dynamic incoming
link configuration) for each client from which it will
accept a PPP link request.
Note: For servers that assign IP addresses from an
IP address pool, it is possible to have more than one
client log in using the same PPP login account. This
makes configuration simpler by requiring fewer PPP
login accounts. For more information about login
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Complex PPP Connection Scenarios
accounts, see Creating a PPP login account, page
50.
•
The server must specify unique local and remote IP
addresses in each client login entry. These addresses
may be specified at configuration time for each login
entry, or a pool of IP addresses may be created from
which PPP chooses at link bringup time. For more
information on how to implement this choice, see
“Configuring a Dynamic Incoming PPP Link” (page
3-49).
•
Each client host agrees to use the remote and local
IP addresses that the PPP server specifies for that
client login.
Client assigns addresses
server configuration:
This requires the following
•
All login entries (that is, dynamic incoming link
configurations) that will be used by clients assigning
the IP addresses must permit IP address negotiation
by not specifying the noipaddr configuration parameter.
•
All login entries that will be used by clients assigning the IP addresses must not specify local or remote
IP addresses.
•
Each client host must specify unique remote and
local IP addresses when negotiating for a PPP link
with the server.
•
Each client host must support IP address negotiation with the server.
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Complex PPP Connection Scenarios
Note: For clients that assign the IP addresses, it is
possible to have two or more of these clients log in
using the same login account. This makes configuration simpler by requiring fewer PPP login accounts.
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Point-to-Point Protocol (PPP)
MIB Support and Logging
MIB Support and Logging
PPP MIB Support
STREAMware PPP supports queries for data about PPP
status from the Simple Network Management Protocol
(SNMP) daemon (snmpd). For PPP to respond to such
queries, the SNMP daemon must be running on the
local system. STREAMware PPP will provide data about
any of the objects within the following two Management Information Bases (MIBs):
•
PPP Link Control Protocol MIB (PPP LCP MIB)
•
PPP IP Network Control Protocol MIB (PPP IPCP
MIB)
The objects contained in each of the above two MIBs are
listed in RFC 1471 and RFC 1473.
Logging PPP
Information
Debugging information about STREAMware PPP activities is available from syslog(3), at the system console, and through the pppstat(1M) command. This
section describes what information is available and
where. See “Troubleshooting PPP” (page 3-78) for help
in interpreting and using this information.
Note: The logging of information degrades system
performance. If you turn on or turn up logging, you
should return it to the default state when done troubleshooting.
PPP debugging information is generated by three
sources:
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Point-to-Point Protocol (PPP)
MIB Support and Logging
PPP driver
Debugging information generated by the PPP driver
is logged through syslog. The debugging information can also be viewed at your terminal by running
pppstat -k. The amount of information generated
is set by a debug parameter (debug=) for each PPP
link configuration in /etc/inet/ppphosts.
The default debug parameter is 0 and can be
changed by manually editing /etc/inet/ppphosts.
To turn on or change logging on an unestablished
link:
1. Open the /etc/inet/ppphosts file.
2. Find the entry for the PPP link being debugged.
3. Change or add the debug parameter in the entry
to debug=0, debug=1, or debug=2.
0. generates no information
1. LCP, IPCP, PAP, and CHAP negotiation information
2. generates all negotiation information and
PPP packets (the packets are in hex format)
4. Close the /etc/inet/ppphosts file. The change to the
debug level will take effect the next time the link
is established or by signaling pppd. (See
“Signaling the PPP Daemon” (page 3-76).)
To turn on or change logging on an established link:
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MIB Support and Logging
ifconfig interface debug debug_number
interface must be an established PPP interface such
as ppp0 and debug_number a value of 0, 1, or 2.
PPP daemon
The PPP daemon generates four types of messages:
warning, error, alert, and info. These messages are
automatically logged through syslog. The debugging information can also be viewed at your terminal by running pppstat -m.
The debug level is set using the -d option with pppd or
by sending SIGUSR1 or SIGUSR2 signals to the PPP
daemon. A debug level of 0 (the default), causes warning, error, and alert messages to be generated through
syslog; a level greater than 0 causes all four types of
messages to be generated. When you use pppstat m, all four message types are displayed.
To log warning, error, alert, and info messages enter:
kill -1USR1 `cat /etc/inet/pppd.pid`
or start pppd with the option -d9.
To return PPP daemon logging to the default state
(turn off the logging of info messages):
kill -1USR2 `cat /etc/inet/pppd.pid`
or kill the daemon and restart it without the -d9 option.
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MIB Support and Logging
UUCP
When PPP requests a UUCP link, the UUCP activity
is logged to the system console (tty01).The amount
of information logged depends on the value of the
pppd debug level described above. Recognized
numbers are 1 to 9, with higher numbers logging
more UUCP information.
This level of logging is determined by pppd logging
level discussed above. Each execution of kill -16
`cat /etc/inet/pppd.pid` increases the logging
level by 1 up to a value of 9. To increase the amount
of information logged to the console about PPPrelated UUCP activity, repeatedly execute:
kill -16 `cat /etc/inet/pppd.pid`
To turn off this logging, execute:
kill -17 `cat /etc/inet/pppd.pid`
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Configuring PPP Links
Configuring PPP Links
To create a PPP link configuration:
1. Determine the type of link required. See “PPP Link
Configurations” (page 3-13).
2. Create an entry in the /etc/inet/ppphosts file for each
link consisting of:
•
elements specific to the type of link being configured
•
elements common to all four types of links.
3. Add entries to other configuration files as required.
These files may include one or more of the following:
•
/etc/inet/pppauth
•
/etc/inet/ppppool
•
/etc/inet/pppfilter
•
/etc/passwd (Never edit this file directly; use the
useradd command.)
•
/etc/group
•
/etc/inet/hosts
•
/usr/lib/uucp/Systems
•
/usr/lib/uucp/Devices
•
/usr/lib/uucp/Dialers
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Point-to-Point Protocol (PPP)
Configuring PPP Links
See “PPP Configuration Files” (page 3-11) for information on the availability of sample starter files for
/etc/inet/ppphosts, /etc/inet/pppauth, /etc/inet/ppppool and
/etc/inet/pppfilter.
Configuring a
Dedicated PPP Link
This type of configuration must only be used with a
serial line that is always up and dedicated to a single
connection. Examples of such lines include a leased line
between buildings or a serial cable connecting two machines.
The configuration files involved in configuring a dedicated PPP link are:
•
/etc/inet/ppphosts - mandatory
•
/etc/inet/hosts - recommended
•
/etc/inet/pppauth - optional
•
/etc/inet/pppfilter - optional
Sample file entries are provided at the end of this section.
/etc/inet/ppphosts File Entries
Create a separate entry in the /etc/inet/ppphosts file for
each dedicated PPP link required. Optional parameters
have default values if they are not specified.
The mandatory parameters for a dedicated link are:
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Configuring PPP Links
remote_addr:local_addr
This must be the first element in the /etc/inet/ppphosts
entry. It specifies an IP address for the remote system and an IP address for the local system. remote_addr:local_addr can also be host names if they
are resolvable without this PPP link. The remote system must agree to use the specified addresses or the
local system will refuse to establish the link.
staticdev=value
staticdev must specify the tty device to use for the
link, such as staticdev=/dev/tty1a.
The optional parameters for a dedicated link consist of
two parameters unique to dedicated links (speed and
clocal) and a number of parameters common to all
types of PPP links.
speed=value
speed sets the line speed in bits-per-second. Its default value is 9600.
clocal
Specifying the clocal parameter causes the open(2)
of the serial port for this link to not wait for an asserted Data Carrier Detect (DCD) signal before returning; it also causes the link to remain up even if
the DCD signal is de-asserted. This parameter is
useful for dedicated links where you want the interface to come up or remain up regardless of the state
of DCD.
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Point-to-Point Protocol (PPP)
Configuring PPP Links
The section “Common /etc/inet/ppphosts Parameters”
(page 3-71) describes the list of PPP configuration parameters common to all types of PPP links.
/etc/inet/hosts File Entries
See /etc/inet/hosts on page 3-12.
/etc/inet/pppauth File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional auth
parameter, ensure that one or more entries exist in the
/etc/inet/pppauth file. These entries depend on whether
the PAP or CHAP authentication protocol will be used
and whether the local host or remote host or both hosts
will require authentication. See the pppauth(4) manual
page in the STREAMware TCP for MP-RAS Administrator's Reference Guide.
/etc/inet/pppfilter File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional filter
parameter, ensure that an entry exists in
/etc/inet/pppfilter with a tag field that matches the value
specified by the optional filter parameter. See the packetfilter(4) manual page in the STREAMware TCP for MPRAS Administrator's Reference Guide.
Example File Entries
/etc/inet/ppphosts file:
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Configuring PPP Links
shaw:yeats staticdev=/dev/tty1a speed=19200 flow=rtscts \
term=2 nak=10 mru=296 auth=pap name=yeatspap filter=dedicated
/etc/inet/hosts
128.2.129.5
135.3.12.9
shaw
yeats
/etc/inet/pppauth
yeatspap
shaw
gregory
manners
/etc/inet/pppfilter
dedicated
Configuring a
Dynamic Incoming
PPP Link
bringup keepup pass
A dynamic incoming link configuration permits the
local host to accept incoming PPP connection requests
via the local system's ttymon(1M) facility. To do this, the
local serial port must be configured to accept dynamic
incoming PPP requests.
A remote host wishing to initiate a PPP link with a local
host must use a PPP login account present in the
/etc/passwd file. For PPP accounts, the local host invokes
/usr/lib/ppp/ppp instead of a standard shell.
/usr/lib/ppp/ppp notifies pppd of the PPP connection
request and passes it the name of the login account. The
daemon finds this name in /etc/inet/ppphosts and builds
an interface and link based on the parameters found
there.
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Point-to-Point Protocol (PPP)
Configuring PPP Links
Creating a PPP login account
To create a PPP login account:
1. Type the following commands:
/usr/sbin/useradd
-d /usr/lib/ppp
-s /usr/lib/ppp <ppplogin>
2. Then change the password for the newly created
account, e.g.:
passwd <ppplogin>
<ppplogin> is the value of the login name you
choose to use. For more information, see useradd.1m.
Configuring and Diagnosing ttymon
Configuring ttymon
Use the following process to configure ttymon to monitor a serial port.
1. Create this script to register ttymon with sac (Service
Access Control):
#!/bin/ksh
#
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Configuring PPP Links
# This script adds a port monitor
#
# Usage: add_port_monitor <port monitor name>
#
sacadm -a -p $1 -t ttymon -c /usr/lib/saf/ttymon -v 1
2. Assume the above script is called
add_port_monitor. To add a port monitor execute:
add_port_monitor ttymon_name
ttymon_name is used as a tag to identify this port
monitor. It can be any name that you desire. For example
add_port_monitor ttymon1
3. Create the following script to assign ports to be
monitored by ttymon_name.
#!/bin/ksh
#
# This script can be used to add a port to be monitored
# by a port monitor. A port moinitor needs to be added
# before this script is ran by using the add_port_monitor
# script.
#
# Usage: add_port <Port Monitor Name> <tty device name>
# <Baud Rate> <SVC Tag>
#
pmadm -a -p $1 -s $4 -i root \
-fu -v 1 -m "`ttyadm -hbr1 -d$2 \
-l $3 -s /usr/bin/login`"
4. Assume the above script is called add_port. Execute
the following command to have ttymon monitor a
port:
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Configuring PPP Links
add_port ttymon_name device_name baud_rate SVC_Tag
where:
•
ttymon_name is the name of a port monitor created using step 2 above
•
device_name is the device name associated with
the port (for example, /dev/tty00h or
/dev/term/s00)
•
baud_rate is a terminal line setting definition in
/etc/ttydefs (see the ttydefs(4) manual page)
•
SVC_Tag is a unique string used to identify the
port being monitored
For example:
add_port ttymon1 /dev/tty00 19200NP 01
Diagnosing ttymon
There are five diagnostic scenarios or procedures for
ttymon. They include:
1. identifying current ttymons registered with sac
2. viewing current serial ports monitored with their
respective ttymon names
3. removing a port from a port monitor
4. removing a port monitor registered with sac
5. killing and restarting a port monitor
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To see the current ttymons that are registered with sac,
enter
sacadm -l
The ttymon entries can be identified by the word
ttymon in the PMTYPE column of the command
output. The name associated with ttymon is in the
PMTAG column.
Here is a sample output:
PMTAG
tcp
ttymon3
PMTYPE
listen
ttymon
FLGS RCNT STATUS
0
ENABLED
1
ENABLED
COMMAND
/usr/lib/saf/listen tcp #
/usr/lib/saf/ttymon #
The second entry is a ttymon entry. If the ttymon is
working properly, the status column will display
ENABLED.
6. To see the current serial ports being monitored with
their respective ttymon names, enter
pmadm -l
The ttymon entries can be identified by the word
ttymon in the PMTYPE column of the command
output. The associated name is in the PMTAG column. The associated device name (serial port) is in
the <PMSPECIFIC> column.
Here is a sample output:
PMTAG
tcp
PMTYPE
SVCTAG
FLGS ID
listen
0
root
/usr/lib/saf/nlps_server #NLPS server
SCHEME
<PMSPECIFIC>
reserved - - c -
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Configuring PPP Links
tcp
ttymon3
listen
lp
/var/spool/lp/fifos/listenS5 #
ttymon
00
u
/usr/bin/login - 9600HW - login:
root
root
- - #
reserved - - p reserved /dev/term/00 hb -
The third entry is a ttymon entry and the monitored
port is /dev/term/00. The ttymon name is ttymon3.
7. To remove a port from a port monitor, enter
pmadm -r -p ttymon_name
-s SVC_Tag
where
•
ttymon_name is the name of the port monitor
monitoring the port. This corresponds to the
name in the PMTAG column of the output from
pmadm -l
•
SVC_Tag is the SVC tag associated with the specific port to be removed. This corresponds to the
tag in the SVCTAG column of the output from
pmadm -l
8. To remove a port monitor that is registered with sac,
enter:
sacadm -r -p ttymon_name
where ttymon_name is the name of the port monitor.
This corresponds to the name in the PMTAG column of the output from sacadm -l.
9. To kill and restart a port monitor, enter
sacadm -k -p ttymon name
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to kill the port monitor and
sacadm -s -p ttymon_name
to restart the port monitor, where ttymon_name is the
name of the port monitor. This corresponds to the
name in the PMTAG column of the output from
sacadm -l.
Configuration Files
The configuration files involved in configuring a dynamic incoming PPP link are:
•
/etc/passwd - mandatory (Do not edit this file directly; use the useradd command.)
•
/etc/group - mandatory
•
/etc/inet/ppphosts - mandatory
•
/etc/inet/hosts - recommended
•
/etc/inet/ppppool - optional
•
/etc/inet/pppauth - optional
•
/etc/inet/pppfilter - optional
Sample file entries are provided at the end of this section.
/etc/passwd File Entries
You must create a login account in the /etc/passwd file on
the local host for each PPP login name you wish to
make available for incoming PPP connections. The program field in the /etc/passwd account entry must contain
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Configuring PPP Links
the file /usr/lib/ppp/ppp instead of a shell program unless
you disable the PPP banner message. Use the useradd(1M) utility to add PPP accounts.
Note:
DO NOT directly edit the /etc/passwd file.
PPP Banner Until the PPP protocol is active on a port,
data sent by the remote host will be echoed, but will not
be processed. To indicate that the PPP protocol is active,
a PPP banner is displayed once the protocol is active.
Any PPP chat script on the remote host must not send
data packets until the banner is displayed. The banner
will appear similar to:
STREAMware PPP version x.xx
with x.xx being the current version.
This banner can be turned off using the -q option. To
turn the banner off, follow a procedure similar to the
one illustrated below:
1. Create a script /usr/lib/ppp/ppp-quiet, which contains
#ksh
/usr/lib/ppp/ppp -q
2. When using useradd to create the PPP login account, include the option -s /usr/lib/ppp/ppp-quiet
/etc/group File Entries
You must create entries in the /etc/group file for any
group entries present in the /etc/passwd entries you create.
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/etc/inet/ppphosts File Entries
Create a separate dynamic incoming link entry in the
/etc/inet/ppphosts file for each PPP login account required. A single account can be used by multiple parties; therefore, a single entry may be the basis for
multiple dynamic incoming links. Optional parameters
have default values if they are not specified.
The mandatory parameters for a dynamic incoming link
entry are the following:
•
The first element in the /etc/inet/ppphosts entry must
be a PPP login_name. It must specify a login account
name that has an entry in the /etc/passwd file.
•
DO NOT include the parameter noipaddr in a dynamic incoming link entry. It is essential for link establishment that PPP perform IP address negotiation
for dynamic incoming links. The absence of the noipaddr parameter ensures that the local host will initiate this negotiation.
•
Include one of three sets of parameters that specify
how the IP addresses for the local and remote hosts
will be assigned. For dynamic incoming PPP links,
the IP addresses can be assigned in any of three
ways:
remote host assigns addresses
If you want the remote host to assign the IP addresses, specify no addresses in the
/etc/inet/ppphosts entry by omitting the remote
and local parameters.
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In this situation, the remote host must provide
the IP addresses for both the local and remote
hosts during PPP negotiation or the local host refuses the connection request.
local host assigns addresses at configuration time
If you want the local host to assign the IP addresses at configuration time and you always
want these two addresses to be used on links
using this login account, include the following
parameters in the /etc/inet/ppphosts entry:
•
assign a local IP address to the parameter local in the /etc/inet/ppphosts entry
•
assign a remote IP address to the parameter
remote in the /etc/inet/ppphosts entry
The remote host must agree to use the specified
addresses or the local host refuses the connection request.
local host assigns addresses from pool at link
bringup time
If you want the local host to assign the IP addresses at link bringup time from a pool of remote:local IP address pairs, configure the PPP
link as follows:
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•
Specify the value +tag for the parameter remote in the /etc/inet/ppphosts entry for the
link. tag must be a string matching a tag entry in the PPP configuration file
/etc/inet/ppppool. This entry in /etc/inet/ppppool
must include one or more remote: local IP address pairs. When building a network interface for the link, pppd tries each pair in
succession until it finds one for which it can
build an interface. If none of the pairs works,
the local host refuses the PPP link request.
See the ppppool(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference Guide.
•
The local parameter in the /etc/inet/ppphosts
entry for the link can be left out. If any value
is specified, pppd ignores it.
The optional /etc/inet/ppphosts parameters for a dynamic
incoming link consist of a number of parameters common to all types of PPP links. These are described in
“Common /etc/inet/ppphosts Parameters” (page 3-71).
/etc/inet/hosts File Entries
See /etc/inet/hosts on page 3-12.
/etc/inet/ppppool File Entries
If IP addresses are assigned to a dynamic incoming link
from a pool of addresses (see above), an entry of IP
addresses must exist in the /etc/inet/ppppool file. This
entry must have a tag value that matches that specified
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in the /etc/inet/ppphosts entry for the link. See the
ppppool(4) manual page in the STREAMware TCP for
MP-RAS Administrator's Reference Guide for more information on this file.
/etc/inet/pppauth File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional auth
parameter, ensure that one or more entries exist in the
/etc/inet/pppauth file. The entries required in
/etc/inet/pppauth depend on whether the PAP or CHAP
authentication protocol will be used and whether the
local host or remote host or both hosts will require
authentication. See the pppauth(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference
Guide.
/etc/inet/pppfilter File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional filter
parameter, ensure that an entry exists in
/etc/inet/pppfilter with a tag field that matches the value
specified by the optional filter parameter. See the packetfilter(4) manual page in the STREAMware TCP for MPRAS Administrator's Reference Guide.
Example File Entries
/etc/passwd
nppp:x:11:9:0000-ppp(0000):/usr/spool/uucppublic:/usr/lib/ppp/ppp
/etc/group
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Configuring PPP Links
ppp::9:root,ppp
/etc/inet/ppphosts file:
nppp idle=30 term=2 nak=10 mru=296 auth=pap \
name=yeatspap filter=ppp4 remote=+pool1
/etc/inet/ppppool
pool1
192.35.54.1:192.35.54.90\
128.212.99.53:128.212.99.90\
128.212.44.44:128.212.44.90
/etc/inet/pppauth
yeatspap gregory
shaw
manners
/etc/inet/pppfilter
ppp4
bringup
pass
keepup
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89\
\
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89 and !icmp(0) == 9\
and !icmp(0) == 10
Configuring a
Dynamic Outgoing
PPP Link
This type of PPP link provides for establishing outgoing
PPP connections over UUCP links; UUCP facilities establish a link between the two machines before PPP
uses the connection. A dynamic outgoing link is similar
to a manual outgoing link. See “Configuring a Manual
Outgoing PPP Link” (page 3-66) for the differences.
The configuration files involved in configuring a dynamic outgoing PPP link are:
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Configuring PPP Links
•
/etc/inet/ppphosts - mandatory
•
/usr/lib/uucp/Systems - mandatory
•
/usr/lib/uucp/Devices - mandatory
•
/usr/lib/uucp/Dialers - mandatory
•
/etc/inet/hosts - recommended
•
/etc/inet/pppauth - optional
•
/etc/inet/pppfilter - recommended
Sample file entries are provided at the end of this section.
/etc/inet/ppphosts File Entries
Create a separate entry in the /etc/inet/ppphosts file for
each dynamic outgoing PPP link required. Optional
parameters have default values if they are not specified.
The mandatory parameters for a dynamic outgoing link
are:
remote_addr:local_addr
This must be the first element in the /etc/inet/ppphosts
entry. It must specify an IP address for the remote
system and an IP address for the local system. remote_addr:local_addr can also be host names if they
are resolvable without this PPP link. The remote system must agree to use the specified addresses or the
local system will refuse to establish the link.
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uucp=value
The value is the name of the host to which to connect
via UUCP. By default, the value of the uucp parameter is the remote_addr half of the first element in the
/etc/inet/ppphosts entry. This value must have an entry in the /usr/lib/uucp/Systems file. See the section
“UUCP File Entries” below for more information.
The optional /etc/inet/ppphosts parameters for a dynamic
outgoing link consist of one parameter unique to outgoing links (retry) and a number of parameters common
to all types of PPP links.
retry=num
The value num specifies the number of times UUCP
will attempt to establish a UUCP link before giving
up. The default value is 2.
The section “Common /etc/inet/ppphosts Parameters”
(page 3-71) describes the list of PPP configuration parameters common to all types of PPP links.
UUCP File Entries
The /usr/lib/uucp/Systems file must contain an entry
whose first element is the value specified in the
/etc/inet/ppphosts file with the uucp parameter. The
/usr/lib/uucp/Devices file and the /usr/lib/uucp/Dialers file
must contain entries that support the entry in the Systems file, enabling the UUCP facility to establish a connection to the remote host specified in the
/etc/inet/ppphosts entry.
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See the section “UUCP Facility Use for Outgoing PPP
Links” (page 3-21) for more information on the interaction between UUCP and dynamic outgoing PPP links.
See “Basic Networking Utilities” in the NCR UNIX
SVR4 MP-RAS Administrator Guide: Command Line Interface for more information on the UUCP facility.
/etc/inet/hosts File Entries
See /etc/inet/hosts on page 3-12.
/etc/inet/pppauth File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional auth
parameter, ensure that one or more entries exist in the
/etc/inet/pppauth file. The entries required in
/etc/inet/pppauth depend on whether the PAP or CHAP
authentication protocol will be used and whether the
local host or remote host or both hosts will require
authentication. See the pppauth(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference
Guide for details.
/etc/inet/pppfilter File Entries - Recommended
If the /etc/inet/ppphosts entry includes the optional filter
parameter, an entry must exist in /etc/inet/pppfilter with
a tag field that matches the value specified by the optional filter parameter. See the packetfilter(4) manual
page in the STREAMware TCP for MP-RAS Administrator's Reference Guide for details.
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Configuring PPP Links
See “PPP Packet Filtering” (page 3-18) for a default
specification recommended for this type of link.
Example File Entries
/etc/inet/ppphosts file:
shaw:yeats uucp=ice term=2 nak=10 mru=296 proxy \
auth=pap name=yeatspap filter=ppp4
/etc/uucp/Systems file:
ice Any ACU 19200NP 267 ”” \r\d\r\c ogin: pppconn \
ssword: \d\dppp\d\d
/etc/uucp/Devices file:
ACU term/s01,M - 19200NP USRv32bis
/etc/uucp/Dialer file:
USRv32bis =,-, “” AT&F OK ATB0E0X7&B1&H1&I0&K3&R2&S1 \
OK ATS01=1S02=255S19=0 OK ATDT\T CONNECT
/etc/inet/hosts
128.2.129.5
135.3.12.9
shaw
yeats
/etc/inet/pppauth
yeatspap gregory
shaw
manners
/etc/inet/pppfilter
ppp4
bringup
!port ntp and !port who and !port route\
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Configuring PPP Links
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89\
pass
keepup
\
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89 and !icmp(0) == 9\
and !icmp(0) == 10
Configuring a Manual
Outgoing PPP Link
A manual outgoing link is similar to a dynamic outgoing link in that both require the local host to initiate the
PPP connection and both use UUCP facilities over
which to establish the connection. The major difference
between dynamic outgoing and manual outgoing links
is that manual outgoing permits the remote host to
assign one or both of the IP addresses that define the
endpoints of the link. Dynamic outgoing requires the
local host to assign both addresses.
A dynamic outgoing link is established dynamically
(transparent to the user) when a network application
requires a connection with a remote host over a PPP
link. A manual outgoing link requires that the network
application user:
1. Run the pppattach command to establish the link.
2. Run the ifconfig or netstat command to learn the
remote IP address that the remote system assigned
to the link.
3. Run the network application using the remote IP
address assigned to the link.
The configuration files involved in configuring a manual outgoing PPP link are:
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Configuring PPP Links
•
/etc/inet/ppphosts - mandatory
•
/usr/lib/uucp/Systems - mandatory
•
/usr/lib/uucp/Devices - mandatory
•
/usr/lib/uucp/Dialers - mandatory
•
/etc/inet/hosts - recommended
•
/etc/inet/pppauth - optional
•
/etc/inet/pppfilter - recommended
Sample file entries are provided at the end of this section.
/etc/inet/ppphosts File Entries
Create a separate entry in the /etc/inet/ppphosts file for
each manual outgoing PPP link required. Optional parameters have default values if they are not specified.
The mandatory parameters for a manual outgoing link
are:
remote_addr:local_addr
This must be the first element in the /etc/inet/ppphosts
entry. It must be a colon-separated pair of host
identifiers such as:
132.147.118.7:132.147.246.8
Either identifier can be an IP address, a host name,
or a zero placeholder. Examples of these combinations are shown below:
0.0.0.0:0.0.0.0
0.0.0.0:132.147.118.7
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0.0.0.0:rhine
132.147.118.7:132.147.224.8
132.147.118.7:prague
rhine:prague
When reading this link configuration, pppd uses the
first identifier to represent the remote host and the
second identifier to represent the local host. If an
identifier is a host name, it must be resolvable without the link being configured by this entry. A zero
placeholder indicates that the remote host must
provide the IP address or the local host will drop the
connection.
attach=name
The value of name must be unique to this link configuration. It is passed to the pppattach command to
cause a link based on this configuration to be established. For more information, see pppattach(4) in
the STREAMware TCP for MP-RAS Administrator's
Reference Guide.
uucp=value
The value is the name of the host to which to connect
via UUCP. By default, the value of the uucp parameter is the remote_addr half of the first element in the
/etc/inet/ppphosts entry. This value must have an entry in the /usr/lib/uucp/Systems file. See the section
“UUCP File Entries” below for more information.
The optional /etc/inet/ppphosts parameters for a manual
outgoing link consist of one parameter unique to outgoing links (retry) and a number of parameters common
to all types of PPP links.
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Configuring PPP Links
retry=num
The value num specifies the number of times UUCP
will attempt to establish a UUCP link before giving
up. The default value is 2.
The section “Common /etc/inet/ppphosts Parameters”
(page 3-71) describes the list of PPP configuration parameters common to all types of PPP links.
UUCP File Entries
The /usr/lib/uucp/Systems file must contain an entry
whose first element is the value specified in the
/etc/inet/ppphosts file with the uucp parameter. The
/usr/lib/uucp/Devices file and the /usr/lib/uucp/Dialers file
must contain entries that support the entry in the Systems file, enabling the UUCP facility to establish a connection to the remote host specified in the
/etc/inet/ppphosts entry.
See the section “UUCP Facility Use for Outgoing PPP
Links” (page 3-21) for more information on the interaction between UUCP and outgoing PPP links.
See “Basic Networking Utilities” in the NCR UNIX
SVR4 MP-RAS Administrator Guide: Command Line Interface.
/etc/inet/hosts File Entries
See /etc/inet/hosts on page 3-12.
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Configuring PPP Links
/etc/inet/pppauth File Entries - Optional
If the /etc/inet/ppphosts entry includes the optional auth
parameter, one or more entries must exist in the
/etc/inet/pppauth file. The entries required in
/etc/inet/pppauth depend on whether the PAP or CHAP
authentication protocol will be used and whether the
local host or remote host or both hosts will require
authentication. See pppauth(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference
Guide.
/etc/inet/pppfilter File Entries - Recommended
If the /etc/inet/ppphosts entry includes the optional filter
parameter, an entry must exist in /etc/inet/pppfilter with
a tag field that matches the value specified by the optional filter parameter. See the packetfilter(4) manual
page in the STREAMware TCP for MP-RAS Administrator's Reference Guide.
See “PPP Packet Filtering” (page 3-18) for a default
specification recommended for this type of link.
Example File Entries
/etc/inet/ppphosts file:
shaw:yeats uucp=ice term=2 nak=10 mru=296 proxy \
auth=pap name=yeatspap filter=ppp4
/etc/uucp/Systems file: (??these Systems files appear incorrect)
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ice Any ACU 19200NP 267 “” \r\d\r\c ogin:pppconn \
ssword: \d\dppp\d\d
/etc/uucp/Devices file:
ACU term/s01,M - 19200NP USRv32bis
/etc/uucp/Dialer file:
USRv32bis =,-, “” AT&F OK ATB0E0X7&B1&H1&I0&K3&R2&S1 \
OK ATS01=1S02=255S19=0 OK ATDT\T CONNECT
/etc/inet/hosts
128.2.129.5
135.3.12.9
shaw
yeats
/etc/inet/pppauth
yeatspap gregory
shaw
manners
/etc/inet/pppfilter
ppp4
bringup
pass
keepup
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89\
\
!port ntp and !port who and !port route\
and !port timed and !port bgp and !ip proto 8\
and !ip proto 63 and !ip proto 89 and !icmp(0) == 9\
and !icmp(0) == 10
Common
/etc/inet/ppphosts
Parameters
The following parameters are common to all four types
of PPP link configurations. Specifying any of these parameters is optional. Details for these parameters can be
found in the ppphosts(4) manual page in the STREAMware TCP for MP-RAS Administrator’s Reference Guide.
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Communications Parameters
flow=control
filter=tag
See the section, “PPP Packet Filtering” (page 3-18)
for information on default tag values. To override
the defaults, create a packet filter specification entry
in the file /etc/inet/pppfilter. See packetfilter(4) in the
STREAMware TCP for MP-RAS Administrator's Reference Guide for the format of the /etc/inet/pppfilter file.
debug=num
See “Logging PPP Information” (page 3-41).
proxy
For more information on proxy ARP, see “Proxy
ARP” (page 3-23).
Timer Parameters
idle=idle_time
reqtmout=timeout
conf=num
term=num
nak=num
See ppphosts(4) in the STREAMware TCP for MPRAS Administrator’s Reference Guide for specific
parameter information.
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Link Parameters
mru=num
accm=num
This option provides a way to negotiate the use of
control character mapping on asynchronous links.
By default, PPP maps all control characters into an
appropriate two character sequence. However, it is
rarely necessary to map all control characters and often it is unnecessary to map any characters. A user
may use this option to inform the peer which control characters must remain mapped and which control characters need not remain mapped when the
peer sends them. The peer may still send these control characters in mapped format if it is necessary
because of constraints at the peer.
The Async-Control-Character-Map field is four octets and indicates the new async control character
map. The map is encoded in big-endian fashion
where each numbered bit corresponds to the ASCII
control character of the same value. If the bit is
cleared to zero, then that ASCII control character
need not be mapped. If the bit is set to one, that
ASCII control character must remain mapped. For
example, if bit 19 is set to zero, then the ASCII control character 19 (DC3, Control-S) may be sent in the
clear.
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nomgc
noprotcomp
noaccomp
See ppphosts(4) in the STREAMware TCP for MPRAS Administrator’s Reference Guide for specific
parameter information.
Authentication Parameters
For more information on PPP authentication, see “PPP
Authentication Methods” (page 3-17).
auth=prot
authtmout=tmout
name=hostid
See ppphosts(4) in the STREAMware TCP for MPRAS Administrator’s Reference Guide for specific
parameter information.
IP Parameters
noipaddr
This parameter must be omitted if configuring a dynamic incoming interface and the local and remote
IP addresses are not specified in the local configuration. For all other interface configurations, omit this
parameter if you wish to tell the remote system
what the local and remote IP addresses are set to
and confirm that the remote host is using these addresses. For more information on the importance of
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IP address negotiation, see “PPP Negotiation” (page
3-26).
rfc1172addr
novj
maxslot=slots
noslotcomp
mask=netmask
See ppphosts(4) in the STREAMware TCP for MPRAS Administrator’s Reference Guide for specific
parameter information.
Other Parameters
old
See ppphosts(4) in the STREAMware TCP for MPRAS Administrator’s Reference Guide for specific
parameter information.
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Administering PPP
Administering PPP
STREAMware PPP requires very little in the way of
administration beyond the configuration, reconfiguration, and removal of PPP links. One administrative task
is to signal pppd to read in changes to PPP configuration. This is described in “Signaling the PPP Daemon”
(page 3-76).
pppstat
A PPP command, pppstat, provides the following PPP
information:
•
PPP interface statistics
•
established PPP connections
•
debugging information from the PPP daemon
pppd(1M)
•
debugging information from the PPP driver ppp(7)
See the manual page pppstat(1M) in the STREAMware
TCP for MP-RAS Administrator's Reference Guide.
Signaling the PPP
Daemon
3-76
The PPP daemon is the PPP component that reads the
PPP configuration files. As stated in “PPP Configuration
Files” (page 3-11) , pppd reads the /etc/inet/ppphosts and
/etc/inet/pppfilter files when it starts. If you change these
files pppd must reread them for the changes to take
effect. To have pppd reread these files:
•
restart pppd
•
send the daemon a SIGHUP signal.
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Point-to-Point Protocol (PPP)
Administering PPP
The daemon is restarted anytime TCP/IP is stopped
and then started again. To avoid stopping and starting
TCP/IP, signal the daemon by executing the following
command:
kill -HUP `cat /etc/inet/pppd.pid`
For dedicated or dynamic outgoing links, the PPP interface is torn down and rebuilt if one of the following
parameters changes or is added:
•
remote or local address
•
netmask (mask)
•
device (staticdev)
•
speed (speed)
•
flow control (flow) on dedicated links
•
filter tag used by interface in /etc/inet/pppfilter
•
filter parameter (filter)
If other parameters change, they take effect the next
time the PPP connection is brought down and back up.
For dynamic incoming or manual outgoing links,
changes take effect the next time the PPP connection is
brought down and back up.
You do not need to signal pppd if you manually change
the /etc/inet/pppauth file. The daemon reads this file
during PPP negotiation and so reads it automatically
when establishing a link if authentication is required.
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Troubleshooting PPP
Between the system administrator's configuration of a
PPP link and the transfer of application data over that
link are many steps, almost all of which are transparent
to the application user and the system administrator.
Failure to achieve a successful PPP connection can occur
during many of these steps. This section describes
troubleshooting procedures and debugging information
that can make these steps visible for identifying the
reason for failure.
These steps can be grouped into two stages:
•
host-to-host connectivity
Host-to-host connectivity means the calling host and
the called host have established a physical connection and can exchange data. The steps to reaching
host-to-host connectivity vary significantly depending on the type of PPP link (that is, whether it is a
dedicated, dynamic incoming, dynamic outgoing, or
manual outgoing type link).
•
PPP negotiation
Once host-to-host connectivity is established, the
PPP protocol requires that the two hosts negotiate
PPP characteristics for the connection before they
can exchange application data. Because PPP negotiation is defined by the PPP protocol, it is similar
for all STREAMware PPP links.
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The following figure illustrates a recommended procedure for troubleshooting PPP links. The last step covers
the debugging of PPP negotiation for all types of
STREAMware PPP links. The remaining steps cover the
debugging of host-to-host connectivity and vary depending on the type of STREAMware PPP link being
debugged. Each box in the figure references a letter
from A-G. The list following the figure maps each letter
to a particular troubleshooting subsection. Because the
functionality verified by the subsections referenced in
the lower boxes is dependent on the functionality verified in any boxes above, it is best to perform the troubleshooting steps in the order shown.
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Troubleshooting PPP
troublehooting
outgoing PPP
links
dynamic; manual;
see B
see C
verify that PPP
network interface
exists; see E
verify integrity of
dedicated serial
line; see F
verify dedicated
host-to-host
connectivity;see A
troubleshooting
dynamic incoming
PPP links; see B
verify that the remote
system can login and
that the PPP shell has
started; see D
verify UUCP
connectivity on
serial line; see G
verify dynamic outgoing
host-to-host connectivity;
see B
troubleshooting
PPP negotiation;
see H
A “Troubleshooting Dedicated PPP Link Connectivity” (page 3-82)
B “Troubleshooting Dynamic Outgoing PPP Link
Connectivity” (page 3-88)
C
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Troubleshooting PPP
nectivity” (page 3-92)
D “Troubleshooting Dynamic Incoming PPP Links”
(page 3-97)
E “Verifying the Existence of a PPP Network Interface” (page 3-84)
F “Verifying Integrity of PPP-Dedicated Serial Line”
(page 3-86)
G “Verifying UUCP Connectivity Before PPP Use”
(page 3-96)
H
“Troubleshooting PPP Negotiation” (page 3-99)
The debugging procedures rely upon the information
logged by the various processes involved in establishing
a PPP link. This logging information is described in
“Logging PPP Information” (page 3-41) .
Note: The pppstat command displays in real time PPP
information useful for debugging. See the pppstat(1M)
manual page in the STREAMware TCP for MP-RAS Administrator's Reference Guide.
The debugging procedures for dedicated and dynamic
outgoing PPP links recommend using the networking
command ping when testing these types of PPP links
for host-to-host connectivity. You can use other networking commands, such as ftp or telnet, but ping is much
simpler, requiring less activity for success. If an application such as ftp fails, the problem could be in many
places throughout the protocol stack or with the application itself. Because ping uses icmp, it relies only on the
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Troubleshooting PPP
protocol stack up through the IP layer. If ping is successful, the problem is less likely to be with PPP. This is
because most of what PPP implements must succeed for
ping to succeed. See ping(7) in the STREAMware TCP
for MP-RAS Administrator's Reference Guide for more
information on ping.
To troubleshoot a dedicated PPP link:
Troubleshooting
Dedicated PPP Link
Connectivity
1. Verify the existence of a PPP network interface for
the dedicated PPP link you are troubleshooting. (See
“Verifying the Existence of a PPP Network Interface” (page 3-84).)
2. Verify the integrity of the serial line being used for
the dedicated PPP link you are troubleshooting. (See
“Verifying Integrity of PPP-Dedicated Serial Line”
(page 3-86).)
3. Verify host-to-host connectivity on the dedicated
PPP link you are troubleshooting, as follows:
a. Turn on PPP driver and PPP daemon logging
See “Logging PPP Information” (page 3-41).
b. Execute the following command:
ping remote_host_IP_address
If ping fails, it may fail with an error message. Below is one possible message:
ping send: Network is unreachable
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This error message indicates that the network address of the remote host is different
from that of the local host. Make sure that
the network portion of the remote host's IP
address is correct. (See Appendix B, “Internet
Addressing” for a discussion of the network
portion of the IP address.) For machines on
the same network, the network part of the IP
addresses for the local host and the remote
host should match. If the machines are not
on the same network, you need to configure
a gateway to route packets between the two
networks.
If ping hangs with no response, make sure
that the IP address used on the command
line is correct. It should be the value assigned to the machine connected to the other
end of the dedicated link. If the IP address
appears to be correct, look in the log file
where the PPP driver and PPP daemon log
information has been collected. By default,
this file is /var/adm/usererr/error.*. See the
manual page syslog.conf(4) for more information. The following example log file and
the description below the example show the
steps PPP uses to achieve host-to-host connectivity. You can view the log file to see if
these steps have been successful.
1 Mar 14 09:31:54 127.0.0.1
2 Mar 14 09:31:58 127.0.0.1
3 Mar 14 09:31:58 127.0.0.1
4 Mar 14 09:31:59 127.0.0.1
.6->132.147.118.9) is 84
pppd[318]:
pppd[318]:
pppd[318]:
pppd[318]:
ppp_add_inf: 132.147.118.6 --> 132.147.118.9
Set static PPP on tty4d
ppp_add_conn
Assigned link id for dedicated link (132.147.118
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Troubleshooting PPP
line 1
pppd builds the PPP network interface for
the link
line 2
pppd links the tty specified in the PPP link
configuration under the PPP driver
line 4
pppd assigns a link ID (84) to the dedicated
link
With knowledge of either the local or remote
IP address for the PPP link you are troubleshooting, you can search on either in the
/var/adm/usererr/error.* file to see if the above
activities completed successfully. Success is
achieved if pppd assigned a link ID.
If you can ping the remote IP address, ping
using the remote host name. See “Using Ping
to Test Reachability Using Host Names”
(page 3-107) for the command, possible error
messages, and resolutions.
Each PPP link must have a unique PPP network inter-
Verifying the Existence face. For a dedicated PPP link or a dynamic outgoing
PPP link, building this interface is the first action that
of a PPP Network
pppd does after reading the PPP link configuration. If
Interface
the network interface cannot be successfully built for
these types of PPP links, no further progress toward
establishing the PPP link is possible.
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To verify the existence of a PPP network interface for
your dedicated or dynamic outgoing PPP link:
ifconfig -a
ifconfig will display output similar to:
net1: lags=4043<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet
132.147.246.7 netmask ffffff00 broadcast
132.147.246.255 ether 00:00:c0:06:95:18
lo0: flags=4049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 8232 inet
127.0.0.1 netmask ff000000
ppp0: flags=4070<POINTOPOINT,WANTIOCTLS,RUNNING,MULTICAST> mtu 1500 inet
132.147.246.6 --> 132.147.246.8 netmask ffffff00
ppp1: flags=4070<POINTOPOINT,WANTIOCTLS,RUNNING,MULTICAST> mtu 1500 inet 1
32.147.246.7 --> 132.147.246.9 netmask ffffff00
ppp2: flags=4070<POINTOPOINT,WANTIOCTLS,RUNNING,MULTICAST> mtu 1500 inet
132.147.246.10 --> 132.147.246.11 netmask ffffff00
The entries for ppp0, ppp1, and ppp2 are examples of
what will appear for PPP network interfaces that exist.
To determine which entry reflects the network interface
for the PPP link you are troubleshooting, you must
know the IP addresses specified in the PPP link configuration. In the entry for ppp2, for example,
132.147.246.10 is the IP address being used for the local
host and 132.147.246.11 is the IP address being used for
the remote host.
If a network interface entry is not displayed for the PPP
link, PPP was unable to build an interface. Perform the
following:
•
Check that the source and destination addresses in
the PPP link configuration in /etc/inet/ppphosts are
correct.
•
Force pppd to reread the /etc/inet/ppphosts file:
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Troubleshooting PPP
kill -1 `cat /etc/inet/pppd.pid`
If a network interface still fails to appear for this link,
check the syslogd logging file for clues.
If a network interface entry does exist for the PPP link
you are troubleshooting:
Verifying Integrity of
PPP-Dedicated Serial
Line
•
Check that the source and destination addresses are
correct and have corresponding entries on the remote host.
•
Check the netmasks of both machines. An incorrect
netmask can render a host or network unreachable.
•
Go to “Verifying Integrity of PPP-Dedicated Serial
Line” (page 3-86) to continue troubleshooting a
dedicated PPP link.
•
Go to “Troubleshooting Dynamic Outgoing PPP
Link Connectivity” page 3-88) to continue troubleshooting a dynamic outgoing PPP link.
For PPP to run over a dedicated serial line, check the
line itself and its connections at each end:
•
Verify the soundness of the line connections.
•
Verify that the local and remote systems on the connection are set to use the same data transfer speed.
For the local STREAMware system, check the value
of the speed parameter for this PPP link in the
/etc/inet/ppphosts file. For the remote system, check
the data transfer speed setting in its configuration
for this link.
Test the serial line as follows if the line connections appear sound but the problem still appears to be in the
line. This procedure requires that:
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Troubleshooting PPP
•
You have access to the remote system.
•
The remote system is running the UNIX operating
system.
1. Log in at both machines as root.
2. Disable PPP for this serial line at both machines.
3. Configure the serial port at the remote machine to
accept an incoming call.
4. At the local machine, edit the file
/usr/lib/uucp/Devices to be sure that the tty port for
the serial line being used is configured for direct access and both systems specify the same speed. For
example:
Direct tty1a - 9600 direct
5. Enter the following command on the source machine.
cu -l tty_number dir
Your serial line is sound if the screen displays connected and the login prompt appears. Type ~. at the
beginning of a line to exit the cu program.
If there is no response, the problem probably lies
with the cable. Check the cable's connections or try
another cable. If an error message appears, see the
information on “Basic Networking Utilities” in the
NCR UNIX SVR4 MP-RAS Administrator Guide:
Command Line Interface.
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If the serial line appears sound, go back to
“Troubleshooting Dedicated PPP Link Connectivity”
(page 3-82) to continue troubleshooting.
To troubleshoot a dynamic outgoing PPP link:
Troubleshooting
Dynamic Outgoing
PPP Link Connectivity
1. Verify the existence of a PPP network interface for
the dynamic outgoing PPP link you are troubleshooting. See “Verifying the Existence of a PPP
Network Interface” (page 3-84).
2. Verify that the local host can establish a UUCP connection to the remote host without PPP. See
“Verifying UUCP Connectivity Before PPP Use”
(page 3-96).
3. Verify host-to-host connectivity on the dynamic
outgoing PPP link you are troubleshooting as follows:
a. Turn on PPP driver, PPP daemon, and UUCP
logging. See “Logging PPP Information” (page
3-41) .
b. Execute the following command:
ping remote_host_IP_address
If ping fails, it may fail with an error message. Below is one possible message:
ping send: Network is unreachable
This error message indicates that the network address of the remote host is different
from that of the local host. Make sure that
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Troubleshooting PPP
the network portion of the remote host's IP
address is correct. (See Appendix B, “Internet
Addressing” for a discussion of the network
portion of the IP address.) For machines on
the same network, the network part of the IP
addresses for the local host and the remote
host should match. If the machines are not
on the same network, you need to configure
a gateway to route packets between the two
networks.
Another possible message is:
ping send: No route to host
If this message appears, verify that there is a
route to the remote host in the routing tables.
If ping hangs with no response, make sure
that the IP address used on the command
line is correct. It should be the value assigned to the machine connected to the other
end of the dynamic outgoing link. If the IP
address appears to be correct, look in the log
file where the PPP driver and PPP daemon
log information has been collected. By default, this file is /var/adm/usererr/error.*. See
the manual page syslog.conf(4) for more information. The following example log file
and the description below the example show
the steps PPP uses to achieve host-to-host
connectivity. You can view the log file to see
if these steps have been successful.
1 Mar 14 09:40:40 pppd[396]: ppp_add_inf: 132.147.246.6 --> 132.147.246.7
2 Mar 14 09:44:27 pppd[396]: accept on socket 6
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3 Mar 14 09:44:27 pppd[409]: dial process sent pppd m_type=18, m_pid=409,
m_tty='/dev/tty1A'
4 Mar 14 09:44:27 pppd[396]: pppd_sockread s=7
5 Mar 14 09:44:27 pppd[396]: Connected to remote system: tty=/dev/tty1A,
pid=409,addr=132.147.54.54
6 Mar 14 09:44:27 pppd[396]: ppp_add_conn
7 Mar 14 09:44:27 pppd[396]: Assigned link id for outgoing link (132.147.
246.6->132.147.246.7) is 1
line 1
pppd builds the PPP network interface for
the link.
UUCP connection made
Not shown in this log file is pppd's contacting of the UUCP facility to request a UUCP
connection. This information is logged at the
local host console.
If the modem does not connect, check the
/etc/inet/ppphosts file to verify that the uucp
parameter has the correct value for the remote host and that the value has an entry in
the /usr/lib/uucp/Systems file. Verify that the
entries in the /usr/lib/uucp/Devices and
/usr/lib/uucp/Dialers files are correct for supporting the Systems file entry.
If the modem does connect but then disconnects, you can also use the UUCP error codes
and PPP debugging information to troubleshoot this problem. For example, if the
UUCP error code says something like chat
script failed, you can view the chat script
dialogue between the local and remote hosts
at the console.
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Troubleshooting PPP
If you find that the modem connects but then
disconnects after a short time, the problem
probably lies with the PPP link parameter
negotiation. To debug this type of problem,
see “Troubleshooting PPP Negotiation”
(page 3-99).
line 3
If the UUCP facility successfully connects
with the remote host, pppd receives this information along with the tty of the connection.
line 5
pppd links the tty of that connection under
the PPP driver.
line 7
pppd assigns a link ID (1) to the dynamic
outgoing link.
With knowledge of either the local or remote
IP address for the PPP link you are troubleshooting, you can search on either one in the
/var/adm/usererr/error.* file to see if the above
activities completed successfully. Success is
achieved if pppd assigned a link ID.
If ping is successful when using the IP address of the remote host, you may wish to
test whether one can reach the remote host
using the host names by which it should be
reachable. See “Using Ping to Test Reachability Using Host Names” (page 3-107) for the
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command, possible error messages, and
resolutions.
To troubleshoot a manual outgoing PPP link:
Troubleshooting
Manual Outgoing PPP
Link Connectivity
1. Verify that the local host can establish a UUCP connection to the remote host without PPP. See
“Verifying UUCP Connectivity Before PPP Use”
(page 3-96).
2. Turn on PPP driver, PPP daemon, and UUCP logging. See “Logging PPP Information” (page 3-41).
3. Execute the following command:
pppattach attachname
attachname should be the value of the attach parameter in the link configuration entry for the link you
are troubleshooting.
4. Check to see if pppattach successfully built a network interface for this link by executing:
ifconfig -a
If an interface does exist for the link you are troubleshooting, go step 5. If no interface was built, the local system was unable to establish a PPP link. To
determine where the process broke, look in the
/var/adm/usrerr/error.* file where the PPP driver and
PPP daemon log information has been collected. The
following example log file and the description below
the example show the first steps PPP uses to achieve
host-to-host connectivity. You can view the log file to
see if these steps have been successful. If these steps
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Troubleshooting PPP
have been successful, go to “Troubleshooting PPP
Negotiation” (page 3-99) to troubleshoot the PPP
negotiation, which occurs after host-to-host connectivity has been established.
1 Mar 14 09:44:27 pppd[396]:
2 Mar 14 09:44:27 pppd[409]:
m_tty='/dev/tty1A'
3 Mar 14 09:44:27 pppd[396]:
4 Mar 14 09:44:27 pppd[396]:
id=409
5 Mar 14 09:44:27 pppd[396]:
6 Mar 14 09:44:27 pppd[396]:
is 1
accept on socket 6
dial process sent pppd m_type=18, m_pid=409,
pppd_sockread s=7
Connected to remote system: tty=/dev/tty1A,
ppp_add_conn
Assigned link id for outgoing link (pid:409)
line 2
PPP daemon requests that UUCP establish a
UUCP connection.
UUCP connection made
Not shown in this log file is pppd's contacting of
the UUCP facility to request a UUCP connection.
This information is logged at the local host console.
If the modem does not connect, check the
/etc/inet/ppphosts file to verify that the uucp parameter has the correct value for the remote host
and that the value has an entry in the
/usr/lib/uucp/Systems file. Verify that the entries
in the /usr/lib/uucp/Devices and
/usr/lib/uucp/Dialers files are correct for supporting the Systems file entry.
If the modem does connect but then disconnects,
you can also use the UUCP error codes and PPP
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debugging information to troubleshoot this
problem. For example, if the UUCP error code
says something like chat script failed, you
can view the chat script dialogue between the local and remote hosts at the console.
If you find that the modem connects but then
disconnects after a short time, the problem
probably lies with the PPP link parameter negotiation. To debug this type of problem, see
“Troubleshooting PPP Negotiation” (page 3-99).
line 4
If the UUCP facility successfully connects with
the remote host, pppd receives this information
along with the tty of the connection.
line 5
pppd links the tty of that connection under the
PPP driver.
line 6
pppd assigns a link ID (1) to the dynamic outgoing link.
5. If execution of the pppattach command successfully
builds a network interface, test the interface with the
ping command:
ping remote_host_IP_address
remote_host_IP_address must be the IP address for the
remote host that appeared in the network interface
entry in the ifconfig display.
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If ping fails, it may fail with an error message. Below is one possible message:
ping send: Network is unreachable
This error message indicates that the network address of the remote host is different from that of the
local host. Make sure that the network portion of the
remote host's IP address is correct. (See Appendix B,
“Internet Addressing” for a discussion of the network portion of the IP address.) For machines on
the same network, the network part of the IP addresses for the local host and the remote host should
match. If the machines are not on the same network,
you need to configure a gateway to route packets
between the two networks.
Another possible message is:
ping send: No route to host
If this message appears, verify that there is a route
to the remote host in the routing tables.
If ping hangs with no response, make sure that the
IP address used on the command line is correct.
If ping is successful when using the IP address of
the remote host, you may wish to test whether one
can reach the remote host using the host names by
which it should be reachable. See “Using Ping to
Test Reachability Using Host Names” (page 3-107)
for the command, possible error messages, and
resolutions.
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Verifying UUCP
Connectivity Before
PPP Use
Dynamic outgoing and manual outgoing PPP links use
the UUCP facilities for establishing a physical connection with the remote host. For more information on
PPP's use of UUCP, see “UUCP Facility Use for Outgoing PPP Links” (page 3-21). A problem with establishing
an outgoing PPP link may be caused by UUCP's inability to establish a UUCP link. To verify that the UUCP
facilities are functioning:
1. Enable ttymon at the remote host by executing the
following command there:
enable tty_number
2. Use the cu(1C) command to try to connect to the
remote system. For example, for a PPP connection
on tty1a running at 1200 baud and calling a modem
at extension 5555, enter the following command on
the local machine:
cu -ltty1a -s1200 5555
The modem should dial, connect, and present a
login prompt. If you do not see a login prompt after
many seconds, type ~%B to make sure that the remote modem did not accidentally cycle past the correct baud rate. Try ~%B three times, waiting several
seconds in between each try.
3. If you still do not get a login prompt, make sure that
the entries in your Devices file are correct and that
the remote tty setup is correct.
4. Enter the following command on the local machine,
specifying the remote host name:
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cu hostname
You should get the same results as when you specify the extension number. If you do not, make sure
that the entries in your /usr/lib/uucp/Systems file are
correct.
If you are unable to establish a UUCP link, see the information on “Basic Networking Utilities” in the NCR
UNIX SVR4 MP-RAS Administrator Guide: Command Line
Interface.
If the UUCP link is successfully made, go back to
“Troubleshooting Dynamic Outgoing PPP Link Connectivity” (page 3-88).
Troubleshooting
Dynamic Incoming
PPP Links
Establishment of a dynamic incoming PPP link requires
the following before all else:
•
A successful login to the local host from the remote
host.
•
The startup of a PPP shell on the local host.
Both of the above activities are logged by default to the
file /var/adm/usererr/error.*. See the manual page
syslog.conf(4) in the STREAMware TCP for MP-RAS
Administrator's Reference Guide for more information.
Following the above activities, communication occurs
between the PPP shell and pppd; this activity is also
logged to the same file. Below is a replication of a log
file showing the entries that appear when the above
activities are successful.
1 Feb 22 17:15:36 127.0.0.1 -ppp[350]: login on '/dev/tty1A'
2 Feb 22 17:15:36 127.0.0.1 pppd[207]: accept on socket 5
3 Feb 22 17:15:36 127.0.0.1 -ppp[350]: sent pppd m_type=16, m_pid=350,
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m_tty='/dev/tty1A'
4 Feb 22 17:15:36 127.0.0.1 pppd[207]:
5 Feb 22 17:15:36 127.0.0.1 pppd[207]:
6 Feb 22 17:15:36 127.0.0.1 pppd[207]:
pid=350, name=nppp
7 Feb 22 17:15:37 127.0.0.1 pppd[207]:
8 Feb 22 17:15:37 127.0.0.1 pppd[207]:
link(login:nppp pid:350) is 80
pppd_sockread s=6
read m_type=16
Incoming call on '/dev/tty1A',
Connecting '/dev/tty1A' under PPP
Assigned link id for incoming
remote host login
The remote host must perform a successful login to
the local host before any PPP activity occurs. To
troubleshoot these steps you should see the logging
of information at the console.
line 1
The PPP shell (as represented by -ppp) starts and informs pppd that a PPP login exists on /dev/tty1A.
line 2
pppd acknowledges the login.
line 3
The PPP shell passes additional information to the
daemon.
lines 6-8
pppd acknowledges receipt of an incoming call,
connects the tty under the PPP driver, and assigns a
link ID to the dynamic incoming link.
If you know the tty to which the PPP link you are troubleshooting tried to login or you know the login name
the remote host used, you can search on either in the
/var/adm/usererr/error.* file to see if the above activities
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completed successfully. Success is achieved if pppd
assigned a link ID.
If the PPP shell starts, it is most likely that the above
activities will be successful. Most failures of dynamic
incoming links at this stage occur because the remote
host is unable to login to the local host or because the
login does not start a PPP shell because of incorrect
configuration information. For a description of the required information, see “Configuring a Dynamic Incoming PPP Link” (page 3-49).
If you find that pppd has successfully assigned a link
ID for the PPP link you are troubleshooting, go to
“Troubleshooting PPP negotiation” (page 3-99) to continue troubleshooting.
Troubleshooting PPP
Negotiation
This section assumes host-to-host connectivity between
the local and remote hosts. If this is not the case, see the
appropriate following section first.
•
“Troubleshooting dedicated PPP link connectivity”
(page 3-82)
•
“Troubleshooting Dynamic Outgoing PPP Link
Connectivity” (page 3-88)
•
“Troubleshooting Manual Outgoing PPP Link Connectivity” (page 3-92).
•
“Troubleshooting Dynamic Incoming PPP Links”
(page 3-97
PPP negotiation involves a minimum of three stages
and possibly four. These stages, in order, are:
1. ICP
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2. LCP
3. Authentication
4. IPCP
Authentication is optional. Its presence depends on
whether the local or remote side requires authentication.
A failure may occur at any of these stages, causing the
connection establishment to fail.
Following is an example of the log entries of an example PPP negotiation session.
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Feb 22 17:13:48 127.0.0.1 pppd[207]: Assigned link id for incoming link
(login:nppp pid:327) is 14
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:administrative
open,Initial->Starting
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:low layer
up,Starting->Req_sent
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:Send config_req
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:Receive
config_req+,Req_sent->Ack_Sent
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:Send config_ack
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):ICP:Receive
config_ack,Ack_Sent->Opened
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:low layer up,
Initial->Closed
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:administrative
open,Closed->Req_sent
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Send config_req
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Send option MRU 1500
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Send option ACCM
ffffffff
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Send option auth
PAP
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Send option magic
number 46c6
Feb 22 17:13:48 127.0.0.1 pppd[206]: Link id(14):LCP:Receive
config_ack,Req_sent->Ack_Rcvd
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Feb 22 17:13:48 127.0.0.1 pppd[206]:
1500 (Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
ffffffff (Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
PAP (Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
magic number:f2381e1f(Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
protocol compression (Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
addr&ctl compression (Ack)
Feb 22 17:13:48 127.0.0.1 pppd[206]:
config_req+,Ack_Rcvd->Opened
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:48 127.0.0.1 pppd[206]:
remote MRU:1500
Feb 22 17:13:48 127.0.0.1 pppd[206]:
remote ACCM:ffffffff
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:48 127.0.0.1 pppd[206]:
protocol compression
Feb 22 17:13:48 127.0.0.1 pppd[206]:
protocol compression
Feb 22 17:13:48 127.0.0.1 pppd[206]:
addr&ctl compression
Feb 22 17:13:48 127.0.0.1 pppd[206]:
compression
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:48 127.0.0.1 pppd[206]:
isc.com
Feb 22 17:13:48 127.0.0.1 pppd[206]:
Feb 22 17:13:49 127.0.0.1 pppd[206]:
packet:
Feb 22 17:13:49 127.0.0.1 pppd[206]:
isc.com
Feb 22 17:13:49 127.0.0.1 pppd[206]:
Feb 22 17:13:49 127.0.0.1 pppd[207]:
Feb 22 17:13:49 127.0.0.1 pppd[207]:
Feb 22 17:13:49 127.0.0.1 pppd[207]:
Feb 22 17:13:49 127.0.0.1 pppd[206]:
Link id(14):LCP:Receive option MRU
Link id(14):LCP:Receive option ACCM
Link id(14):LCP:Receive auth option
Link id(14):LCP:Receive option
Link id(14):LCP:Receive option
Link id(14):LCP:Receive option
Link id(14):LCP:Receive
Link id(14):LCP:Send config_ack
Link id(14):LCP negotiated options:
Link id(14): local MRU:1500
Link id(14):
local ACCM:ffffffff
Link id(14):
Link id(14):
Link id(14):
local requires PAP
remote requires PAP
local disable
Link id(14):
remote do
Link id(14):
local disable
Link id(14):
remote do addr&ctl
Link id(14):send a PAP_REQ packet:
Link id(14): PID:mugwump.i88.
Link id(14): PWD:Bull
Link id(14):receive a PAP_REQ
Link id(14):
PID:krusty.i88.
Link id(14): PWD:Blazer
received PPCID_PAP
PPCID_PAP auth success
sent PPCID_PAP
Link id(14):send a PAP_ACK packet
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Feb 22 17:13:49 127.0.0.1 pppd[206]: Link id(14):receive a PAP_ACK packet
Feb 22 17:13:49 127.0.0.1 pppd[206]: Link id(14):IPCP:low layer up,
Initial->Closed
Feb 22 17:13:49 127.0.0.1 pppd[206]: Link id(14):IPCP:administrative
open,Closed->Req_sent
Feb 22 17:13:49 127.0.0.1 pppd[206]: Link id(14):IPCP:Send config_req
Feb 22 17:13:52 127.0.0.1 pppd[207]: received PPCID_PAP
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):receive a PAP_REQ packet:
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):
PID:krusty.i88.isc.com
Feb 22 17:13:52 127.0.0.1 pppd[207]: PPCID_PAP auth success
Feb 22 17:13:52 127.0.0.1 pppd[207]: sent PPCID_PAP
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14): PWD:Blazer
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):send a PAP_ACK packet
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link
id(14):IPCP:Timeout+,Req_sent->Req_sent
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Send config_req
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive option ip
addresses,local:132.147.118.1
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive option ip
addresses,remote:132.147.246.8
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Ack received
option ip addresses
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive option vj
compression MSI:15 CSI:1 (Ack)
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive
config_req+,Req_sent->Ack_Sent
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Send config_ack
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive
config_ack,Ack_Sent->Opened
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14):IPCP negotiated
options:
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14): local address:132.
147.55.44
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14): remote address:132.
147.55.90
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14): local disable vj
compression
Feb 22 17:13:52 127.0.0.1 pppd[206]: Link id(14): remote do vj
compression MSI:16 CSI:1
Feb 22 17:14:32 127.0.0.1 pppd[206]: Link id(14):IPCP:Receive
terminate_req,Opened->Stopping
Feb 22 17:14:32 127.0.0.1 pppd[206]: Link id(14):IPCP:Send
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terminate_ack
Feb 22 17:14:32 127.0.0.1 pppd[206]:
terminate_req,Opened->Stopping
Feb 22 17:14:32 127.0.0.1 pppd[206]:
Feb 22 17:14:32 127.0.0.1 pppd[206]:
Stopping->Starting
Feb 22 17:14:33 127.0.0.1 pppd[206]:
with bad fcs=0x4751 msglen=0x10f
Feb 22 17:14:33 127.0.0.1 pppd[207]:
Feb 22 17:14:33 127.0.0.1 pppd[206]:
>Stopped
Feb 22 17:14:33 127.0.0.1 pppd[206]:
close,Opened->Closing
Feb 22 17:14:33 127.0.0.1 pppd[206]:
Feb 22 17:14:33 127.0.0.1 pppd[206]:
Stopped->Starting
Feb 22 17:14:33 127.0.0.1 pppd[207]:
Feb 22 17:14:33 127.0.0.1 pppd[206]:
terminate_ack,Closing->Closed
Feb 22 17:14:33 127.0.0.1 pppd[206]:
Closed->Initial
Feb 22 17:14:33 127.0.0.1 pppd[207]:
SIGUSR1
Feb 22 17:14:33 127.0.0.1 pppd[207]:
disconnected
Feb 22 17:14:37 127.0.0.1 -ppp[327]:
Link id(14):LCP:Receive
Link id(14):LCP:Send terminate_ack
Link id(14):IPCP:low layer down,
Link id(14):Received frame abort
received PPCID_CLOSE: muxid=14
Link id(14):LCP:Timeout-,StoppingLink id(14):ICP:administrative
Link id(14):ICP:Send terminate_req
Link id(14):LCP:low layer down,
ppp_rm_conn: I_UNLINK muxid=14
Link id(14):ICP:Receive
Link id(14):ICP:low layer down,
ppp_rm_conn sending pid 327
Incoming call on '/dev/tty1A'
sig_hup sig=1
The log file may contain information from many sources
within a host. Using the log to troubleshoot PPP negotiation problems requires a recognition of PPP entries.
All log entries contain a date and time stamp followed
by the name or IP address of the host from which the
log message originated. The next field in a log entry is
the process that inserted the entry and its pid. All PPP
entries are inserted by either pppd or a PPP shell
(shown as -ppp).
Once host-to-host connectivity is established, pppd
assigns a link ID to the connection. The following three
lines show a link ID being assigned to a dynamic in-
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Troubleshooting PPP
coming link, a outgoing link, and a dedicated link, respectively.
Feb 22 17:13:48 127.0.0.1 pppd[207]: Assigned link id for incoming link
(login:nppp pid:327) is 14
Feb 22 19:13:48 127.0.0.1 pppd[207]: Assigned link id for outgoing link
(remote:132.147.118.6) is 17
Feb 22 21:13:48 127.0.0.1 pppd[207]: Assigned link id for dedicated link
(remote:132.147.118.10) is 14
To identify entries for the link you are troubleshooting,
you need to know the login name for dynamic incoming links and the IP address of the remote system for
dedicated or outgoing links.
The stage of negotiation is identified in each entry by
the presence of ICP, LCP or IPCP. Log entries about the
authentication stage do not have an identifier as ICP,
LCP, and IPCP do. They do, however, include either the
string PAP or CHAP, which refer to the two authentication protocols that STREAMware supports.
Examination of the log should progress from ICP,
through LCP and authentication, to IPCP. If a failure
occurs at an earlier stage, the later stages will never
occur. For example, if a failure occurs at the LCP stage,
no authentication or IPCP negotiation will occur. Following is a description of the key information to look
for at each stage.
ICP stage
This stage is implementation specific to STREAMware PPP. (The other three stages are RFC standards.) This stage is for the exchange of information
between the PPP driver and the asyhdlc module on
the local system. A failure at this stage is very rare.
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Line 7 above shows the line that reflects ICP success.
The key element in this entry is the PPP state
change: Ack_Sent->Opened.
LCP stage
The LCP stage is negotiated according to the PPP
Link Control Protocol. The following parameters are
negotiated at this stage: maximum receive units
value, asynchronous control character map, magic
number, authentication protocol, protocol field compression, and address-control field compression.
Lines 8-32 show a typical LCP negotiation.
If authentication or IPCP entries appear for the link
ID you are troubleshooting, then the LCP stage was
successful. If successful, the value/state of the parameters negotiated will be listed in the log file as
shown in lines 25-32 of the example. This list may be
repeated in the log file.
If no authentication or IPCP entries appear, a problem might exist with LCP negotiation. Typical
problems at this stage are:
•
The local host does not receive any good packets
from the remote host. If this occurs, you will see
many LCP entries that say Send, but none that
say Receive. Reasons that this might occur include: a bad checksum in response packets from
the remote host, badly formatted packets from
the remote host, or no packets received from the
remote host.
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Troubleshooting PPP
•
The local and remote hosts disagree about parameters. If this occurs, you will see NAK and Reject entries. A NAK or Reject will be present for
a particular parameter. Try changing the
value/state of the parameter causing the NAK
or rejection.
Authentication stage
As mentioned above, this stage is optional and only
occurs if either the local or remote system requires
authentication for this connection. Lines 33-43 show
a typical authentication negotiation.
If IPCP entries appear for your interface, then the
authentication stage was successful. If no IPCP entries appear and LCP appears to have completed
successfully (no NAKs or Rejects on LCP stage
packets), then a problem is likely with authentication. Look for an authentication entry with a PAP or
CHAP failure indicated. Typical problems here are
the sending of an incorrect password or incorrect
packet ID. See the pppauth(4) manual page in the
STREAMware TCP for MP-RAS Administrator's Reference Guide for more information on authentication
entries and exchanges.
IPCP stage
If all of the preceding stages appear successful but
the connection still fails, the problem is in the IPCP
negotiation stage. The following parameters are negotiated at this stage: IP addresses and Van Jacobson
TCP/IP header compression. The typical problem at
this stage is a disagreement about these parameters
between the local and remote systems. If this occurs,
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you will see a NAK or Reject entry for a particular
parameter. Try changing the value/state of the parameter causing the NAK or rejection.
Using Ping to Test
Reachability Using
Host Names
If ping is successful when using the IP address of the
remote host, you may wish to ping the remote host
using the host names by which it should be reachable:
ping remote_hostname
If ping fails, it may fail with the following message:
ping: unknown host remote_hostname
This error message from ping indicates that the remote_hostname used on the ping command line does not
have an entry in /etc/inet/hosts or is not resolvable with
DNS or NIS. This can be resolved by:
•
Editing the /etc/inet/hosts file on the local host to
include an entry for the remote host.
•
Ensuring that DNS can resolve the remote host
name (if DNS is being used).
•
Ensuring that NIS can resolve the remote host name
(if NIS is being used).
•
Ensuring that users use a correct name for the remote host in case the name being used is incorrect.
If ping fails with the following message (reported
through syslog), your modem may be filtering out control characters:
receiving bad checksum packets
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You can resolve this in either of two ways:
3-108
•
Configure your modem not to filter out control
characters.
•
Try to bring up the PPP link with both sides setting
accm to 0xffffffff.
STREAMware TCP Administrator's Guide
Point-to-Point Protocol (PPP)
For More About PPP
For More About PPP
To obtain more information about PPP files and commands, consult the following manual pages:
Manual Page
Information provided
asyhdlc(7)
asynchronous HDLC device driver
ipf(7)
IP packet filter module
packetfilter(4)
SLIP and PPP packet filter specification
ppp(1M)
PPP login shell
ppp(7)
Point-to-Point Protocol (PPP) and driver
pppattach(1M)
pppattach command
pppauth(4)
PPP authentication database
pppd(1M)
PPP daemon
ppphosts(4)
point-to-point link configuration file
ppppool(4)
IP address pools
pppstat(1M)
PPP status
To get more information about PPP, see the following
Request for Comments (RFCs). For information on how
to obtain RFCs, see “How to Obtain RFCs from the In-
STREAMware TCP Administrator's Guide
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Point-to-Point Protocol (PPP)
For More About PPP
ternet” in the “Introduction” of the STREAMware TCP
for MP-RAS Administrator's Guide .
3-110
RFC
Title
1144
Compressing TCP/IP headers for low-speed serial
links
1172
The Point-to-Point Protocol (PPP) Initial Configuration Options
1332
The PPP Internet Protocol Control Protocol (IPCP)
1334
PPP Authentication Protocols
1471
The Definitions of Managed Objects for the Link
Control Protocol of the Point-to-Point Protocol
1473
The Definitions of Managed Objects for the IP
Network Control Protocol of the Point-to-Point
Protocol
1548
The Point-to-Point Protocol (PPP) for the Transmission of Multi-protocol Datagrams over Pointto-Point Links
STREAMware TCP Administrator's Guide
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