Install guide

Software Version 2.7.6 63
Software Version 2.7.6
C613-10462-00 REV A
Reverse Telnet Without Authentication
Reverse Telnet allows you to connect a device such as a modem to an
asynchronous port, and then to control that device by telneting from your PC
to the router or switch. Reverse Telnet is described in RFC 2217, Telnet Com Port
Control Option. The router or switch listens on a TCP port, and the TCP listen
port number depends on the asyn port number (excluding asyn0), according to
the following formula:
TCP port number = 2000 + asyn port number
For example:
■ the reverse Telnet connection for connection to asyn1 uses the TCP port
number 2001
■ the reverse Telnet connection for connection to asyn5 uses the TCP port
number 2005. Asyn5 would be the first port of the second asynchronous
PIC on the router or switch, when two PICs are plugged into bay 1.
The Telnet connection to the router or switch is authenticated, so when you use
reverse Telnet to access a remote device through the router or switch, you have
to enter a username and password. Some remote devices, such as other routers,
also require authentication. This can mean that you have to enter a username
and password twice. Software Version 2.7.6 simplifies this by allowing you to
establish the initial reverse Telnet connection to the router or switch without
authentication.
To stop reverse Telnet from requiring authentication of the Telnet session, use
the new command:
set rtelnet authentication=off
To see if authentication is turned off, use the command:
show config dynamic=telnet
Command Change Summary
The following table summarises the new command (see Command Reference
Updates).
Command Change
set rtelnet New command