Terminal Server Configuration Using Cisco Routers

Posted by: admin  :  Category: Other

A terminal or comm server provides out-of-band access to multiple devices. A terminal server is essentially a router with multiple, low speed, asynchronous ports that can be connected to the console ports of other devices, such as routers or switches.

The terminal server allows you to use a single point to access the console ports of many devices. A terminal server eliminates the need to move the console cable from device to device. You can also configure a modem on the auxiliary port of the terminal server, to provide dial-up service to many network devices when network connectivity fails.

The Cisco 2509 – 2512 series routers use a CAB-OCTAL-ASYNC to provide eight RJ-45 roll over cable. You can connect each RJ-45 roll over cable to the console port of the managed device. The 2511 router allows for a maximum of 16 devices to be remotely accessible. Alternatively the NM-16A or NM-32A high density async network modules can be installed in the Cisco 2600 and 3600 series routers to provide the same function.

Basic configuration of a terminal server:

router#show running-config
version 12.0

service timestamps debug datetime msec localtime show-timezone

service timestamps log datetime msec localtime show-timezone

service password-encryption


hostname lab-comm-server


enable secret  cisco


username cisco password cisco


ip subnet-zero

no ip domain-lookup


ip host R1 2001

ip host R2 2002

ip host R3 2003

ip host R4 2004

ip host R5 2005

ip host R6 2006

ip host V1 2007

ip host FR 2008



process-max-time 200


interface Loopback1

 ip address

!— This address is used in the IP host commands.

!— Work with loopback interfaces, which are virtual and always available.

 no ip directed-broadcast


interface Ethernet0

 ip address

!—  Use a public IP address to ensure connectivity.

No ip directed-broadcast

 no ip mroute-cache


interface Serial0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache



ip default-gateway

!— This is the default gateway when routing is disabled.

!— For example, if the router is in boot ROM mode.

ip classless

ip route

!— Set the default route for the external network.

no ip http server


line con 0

 transport input all

 line 1 16

 session-timeout 20

!— The session times out after 20 minutes of inactivity.

no exec

!— Unwanted signals from the attached device do not launch.

!— An EXEC session ensures that the line never becomes unavailable

!— due to a rogue EXEC process.

 exec-timeout 0 0

!— This disables exec timeout transport input all.

!— Allow all protocols to use the line.

!— Configure lines 1 – 16 with at least transport input Telnet.

line aux 0

!— Auxiliary port can provide dial backup to the network.

!— Note: This configuration does not implement modem on AUX port modem InOut.

!— Allow auxiliary port to support dialout and dialin connections.

 transport preferred telnet

 transport input all

 speed 38400

 flowcontrol hardware

line vty 0 4

 exec-timeout 60 0

 password <deleted>



2 Responses to “Terminal Server Configuration Using Cisco Routers”

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