I'm experiencing strange behavior with a
Cisco UC520 router.
When I am directly connected to the router and telnet to it using this:
telnet 192.168.1.1 23
Then I get a successful login prompt:
Trying 192.168.1.1... Connected to 192.168.1.1. Escape character is '^]'. Cisco Configuration Assistant. Version: 3.0. Fri Jan 14 11:35:39 EST 2011 User Access Verification Username:
However, when forward the port remotely to another machine:
ssh root@another_machine -R 127.0.0.1:23:220.127.116.11:23
And then on that other machine try and connect to the router via telnet:
telnet 127.0.0.1 23
I get a different message, and immediately disconnected:
Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. SSH-1.99-Cisco-1.25 Connection closed by foreign host.
This seemed really odd so I double checked to make sure I was port forwarding port 23 and not port 22. I also tried mapping the router's name in the
/etc/hosts file of the computer I forwarded ports to, so that I could do
telnet RouterName 23 in case it didn't like the hostname. I also tried using a different forwarding port (
10023) which did not work.
I don't see anything in the
man page for
telnet that indicates there is a
--verbose option like
ssh -v would give, which would be my next step in debugging. I don't see any problems in any of the
/var/log/ files on the machine that the ports are forwarded to.
This seems quite strange and I think what is happening is that somehow the router thinks I'm trying to make an SSH connection instead of a telnet connection.