Using CHAP

In addition, this chapter lists several interoperability issues that exist between Cisco IOS software and Cisco 700 series routers. These issues must be considered if you are connecting your Cisco 700 series router to a router running Cisco IOS software.

This chapter contains the following sections:

SPID Detection (North America only)

In North America, SPIDs can be automatically detected or manually configured. For more information on SPID detection, see "Setting SPID Autodetection (North America only)" and "Setting SPIDs Manually (North America only)" in the "Basic Configurations" chapter.

IP Static Routing and Callback with CHAP Authentication

This section describes how to configure the routers for Internet Protocol (IP) static routing and callback with Challenge Handshake Authentication Protocol (CHAP).

Figure 4-1 illustrates the configuration used in this example.

Figure 4-1: IP Static Routing and Callback with CHAP Authentication

Remote Cisco 765 Command Summary

Following is the command summary for configuring the remote Cisco 765 series router for IP static routing and callback with CHAP authentication:

set switch 5ess
set 1 dir directory_number
set 2 dir directory_number
set system 765
set ppp authentication incoming chap
set ppp secret client
set multidestination on
cd lan
set ip address 192.168.147.9 
set ip netmask 255.255.255.248 
set ip routing on
set ip rip update periodic
set ip rip receive v2
set ip rip version 2
set user 4500
set ppp secret client
set ppp secret host
set ip route destination 0.0.0.0 gateway 172.16.125.1 propagate on
set ip address 172.16.125.7 
set ip netmask 255.255.255.0
set ip routing on
set ip framing none
set ppp callback request always
set 1 ringback number
set 2 ringback number
set number 5558011 
set bridging off
set ip rip update off
set timeout 360
set active
reboot

Multilink PPP is enabled by default. If the Cisco700 series router is dialing into a host that does not support multilink PPP or that does not have multilink PPP enabled, the Cisco700 series router might report a misconfiguration. This is most commonly seen when the Cisco700 series router is connected to equipment from Ascend.

IP Static Routing with CHAP Authentication and MLP

This section describes how to configure the central site Cisco 4500 series router and the remote Cisco 765 series router for IP static routing with Challenge Handshake Authentication Protocol (CHAP) and Multilink Protocol (MLP).

Figure 4-2 is an illustration of the configuration used in this example.

Figure 4-2: IP Static Routing with CHAP Authentication and MLP

Remote Cisco 765 Command Summary

Following is the command summary to configure the remote Cisco 765 series router for IP static routing with CHAP and MLP:

set switch 5ess
set 1 dir directory_number
set 2 dir directory_number
set system 765
set multidestination on
set ppp multilink on
set ppp authentication incoming chap
set ppp authentication outgoing chap
cd lan
set ip address 192.168.147.9 
set ip netmask 255.255.255.248 
set ip routing on
set ip rip update periodic
set user 4500
set ppp secret client
set ip address 172.16.125.7 
set ip netmask 255.255.255.0
set ip routing on
set ip framing none
set ip route destination 0.0.0.0 gateway 172.16.125.1 propagate on
set number 5558011 
set bridging off
set ip rip update off
set ppp secret host
set timeout 360
demand 2 threshold 32 duration 5
set active
reboot

Note The set ppp authentication outgoing chap command in this example is not recommended when connecting to Ascend 4000 or NAS routers.

For detailed information regarding the commands listed here, refer to the Cisco 700 Series Router Command Reference.

IP Static Routing with PAP Authentication and MLP

This section describes how to configure the central site Cisco 4500 series router and the remote Cisco 765 series router for Internet Protocol (IP) static routing with Password Authentication Protocol (PAP) authentication.

Figure 4-3 is an illustration of the configuration used in this example.

Figure 4-3: IP Static Routing with PAP Authentication

Remote Cisco 765 Command Summary

Following is the command summary to configure the remote Cisco 765 series router for IP static routing with PAP authentication:

set switch 5ess
set 1 dir directory_number
set 2 dir directory_number
set system 765
set multidestination on
set ppp multi on
set ppp authentication in pap
set ppp authentication out pap
cd lan
set ip address 192.168.147.9 
set ip netmask 255.255.255.248 
set ip routing on
set ip rip update periodic 
set ip rip receive v2
set ip rip version 2
set user 4500
set ip route destination 0.0.0.0 gateway 172.16.125.1 propagate on
set ip address 172.16.125.7 
set ip netmask 255.255.255.0
set ip routing on
set ip framing none
set ppp clientname 765
set ppp password client
set ppp password host 
set number 5558011
set bridging off
set timeout 360
set active
reboot

For detailed information regarding the commands listed here, refer to the Cisco700 Series Router Command Reference.

IP Unnumbered Static Routing and CHAP with MLP

This section describes how to configure the central site Cisco 4500 series router and the remote Cisco 765 series router for Internet Protocol (IP) unnumbered routing with Challenge Handshake Authentication Protocol (CHAP) authentication and Multilink Protocol (MLP).

Figure 4-4 is an illustration of the configuration used in this example.

Figure 4-4: IP Unnumbered Routing and CHAP Authentication with MLP

Remote Cisco 765 Command Summary

Following is the command summary for configuring the remote Cisco 765 series router for IP unnumbered routing with CHAP authentication and MLP:

set switch 5ess
set system 765
set multidestination on
set ppp multilink on
set ppp authentication incoming chap
set ppp authentication outgoing chap
set ppp secret client
set ppp secret host
cd lan
set ip address 192.168.147.9 
set ip netmask 255.255.255.248 
set ip routing on
set ip rip update periodic
set ip rip receive v2
set ip rip version 2
set user 4500
set ppp secret client
set ip rip update off
set ip routing on
set ip framing none
set ip route destination 0.0.0.0 gateway 0.0.0.0
set number 5558011 
set bridging off
set ppp secret host
set timeout 360
set active
reboot

For detailed information regarding the commands listed here, refer to theCisco700 Series Router Command Reference.

IP Static and IPX Static Routing with CHAP and MLP

This section describes how to configure the central site Cisco 4500 series router and Cisco 765 series router for Internet Protocol (IP) static and Internetwork Packet Exchange (IPX) static routing with Point-to-Point Protocol (PPP) using CHAP and MLP.

Figure 4-5 is an illustration of the configuration used in this example.

Figure 4-5: IP Static and IPX Static Routing with PPP

Remote Cisco 765 Command Summary

Following is the command summary to configure the remote Cisco 765 series router for IP static and IPX static routing with PPP using CHAP and MLP:

set switch 5ess
set 1 dir directory_number
set 2 dir directory_number
set system 765
set multidestination on
set ppp authentication incoming chap
set ppp authentication outgoing chap
set ppp secret client
set ppp secret host
cd lan
set ipx network 1478
set ipx framing 802.2
set ipx routing on
set ipx rip update periodic
set ip address 192.168.147.9
set ip netmask 255.255.255.248
set ip routing on
set ip rip update periodic
set user 4500
set ipx network 32125
set ipx routing on
set ipx route destination 3039e670 gateway 32125:0c08af65
set ipx service name CORP_FS1 type 4 address 3039e670:01:0451
set ipx spoof 10
set ipx rip update off
set ipx framing none
set ip routing on
set ip route destination 0.0.0.0 gateway 172.16.125.1 propagate on
set ip address 172.16.125.7
set ip netmask 255.255.255.0
set ip framing none
set number 5558011
set bridging off
set ip rip update off
set timeout 360
set active
reboot

IPX Static Routing with CHAP and MLP

This section describes how to configure the remote Cisco 765 series router and the central site Cisco 4500 series router for Internetwork Packet Exchange (IPX) static routing with Point-to-Point Protocol (PPP).

Figure 4-6 is an illustration of the configuration used in this example.

Figure 4-6: IPX Static Routing with PPP

Remote Cisco 765 Command Summary

Following is the command summary for configuring the remote Cisco 765 series router for IPX static routing with PPP:

set switch 5ess
set 1 dir directory_number
set 2 dir directory_number
set system 765
set multidestination on
set ppp auth in chap
set ppp secret client
set ppp secret host
set multilink on
cd lan
set ipx network 1478
set ipx framing 802.2
set ipx routing on
set ipx rip update periodic
set user 4500
set ppp secret client
set ipx network 32125
set ipx routing on
set ipx route destination 3039e670 gateway 32125:0c08af65
set ipx service name CORP_FS1 type 4 address 3039e670:01:0451
set ipx spoofing 10
set ipx rip update off
set ipx framing none
set number 5558011
set bridging off
set timeout 360
set active
reboot

For detailed information regarding the commands listed here, refer to theCisco700 Series Router Command Reference.

Multilink PPP Encapsulation

Cisco 700 series routers implement multilink PPP, which is available in Release 11.0(3) or later of Cisco IOS software. You can disable multilink PPP in the following two environments:

You are connecting your Cisco 700 series router to a router running a Cisco IOS release prior to 11.0(3).
You are connecting your Cisco 700 series router to a router running Cisco IOS Release 11.0(3) or later, and you have not configured multilink PPP on that router running Cisco IOS.

Use the set ppp multilink command at the system level to disable multilink PPP, as follows:

766> set ppp multilink off

Dynamic Routing Protocols

Cisco 700 series routers implement RIP Versions 1 and 2 and demand RIP. Demand RIP is not implemented in Cisco IOS software. If you are connecting your router to a router running Cisco IOS software, and you want to use a dynamic routing protocol, you must disable demand RIP.

Use one of the following set ip rip update commands to disable demand RIP:

766> set ip rip update periodic / snapshot

766> set ip rip update none

Note Setting the IP RIP update to periodic maintains the connection indefinitely. This might be a concern if it is not necessary to maintain the line 24 hours a day, 7 days a week; you are paying for connection time that you are not using.

Bridging to a Router Running Cisco IOS Software

It is possible to bridge data over ISDN to and from Cisco ISDN routers. Depending on your network environment, this might be an ideal solution. Bridging offers configuration simplicity with few concerns regarding network address space limitations and unroutable protocols. Bridging also offers compatibility with other products that need to bridge.

When bridging, you do not have the same ISDN line control that routing access lists provide. When bridging protocols such as Novell IPX, AppleTalk, or NetBIOS, it is possible for the ISDN line to remain connected for long periods of time. This can result in high ISDN usage charges. If bridging is the only solution for your environment, we recommend monitoring the ISDN line connection.

Cisco IOS Release 11.1 and earlier limit the number of simultaneous ISDN bridge sessions to one per interface.

Prior to Cisco IOS Release 11.2 (half-bridging), the Cisco IOS must also be configured to the bridging protocol, not the router protocol.

Table of Contents

Using CHAP