A terminal server commonly provides out-of-band access for multiple devices. A terminal server is a router with multiple, low speed, asynchronous ports that are connected to other serial devices, for example, modems or console ports on 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 configure backup scenarios like modems on auxiliary ports for every device. You can also configure a single modem on the auxiliary port of the terminal server, to provide dial-up service to the other devices when network connectivity fails.
This document shows how to configure a terminal server to access only the console ports on other routers through Reverse Telnet. Reverse Telnet allows you to establish a Telnet connection out on the same device you telnet from, but on a different interface. For more information on Reverse Telnet refer to Establishing a Reverse Telnet Session to a Modem.
A terminal server enables organizations to connect devices with serial interface to a local area network (LAN). Products marketed as terminal servers can be very simple devices that do not offer any security functionality, such as data encryption and user authentication. The primary application scenario is to enable serial devices to access network server applications, or vice versa, where security of the data on the LAN is not generally an issue. There are also many terminal servers on the market that have highly advanced security functionality to ensure that only qualified personnel can access various servers and that any data that is transmitted across the LAN, or over the Internet, is encrypted. Usually companies which need a terminal server with these advanced functions want to remotely control, monitor, diagnose and troubleshoot equipment over a telecommunications network.
STEPS TO CONFIGURE TERMINAL SERVER
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#int fa 0/0
Router(config-if)#ip address 10.0.0.1 255.0.0.0
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
terminal(config)#username sachtech privilege 15 password test
terminal(config)#ip ssh version 2
Please create RSA keys (of at least 768 bits size) to enable SSH v2.
terminal(config)#ip domain-name test.com
terminal(config)#crypto key generate rsa
The name for the keys will be: terminal.test.com
Choose the size of the key modulus in the range of 360 to 2048 for your
General Purpose Keys. Choosing a key modulus greater than 512 may take
a few minutes.
How many bits in the modulus : 1024
% Generating 1024 bit RSA keys, keys will be non-exportable…[OK]
terminal(config)#line 0/0/0 0/0/7
terminal(config-line)#transport input all
terminal(config)#enable password local
COMMANDS OF PC
C:\>ssh -l sachtech 10.0.0.1 (to login into same network router)
C:\>ssh -l sachtech:2 10.0.0.1 (to login into another network router )