Why does telnet fail after a few connections?

Oct 05, 2006 1 Replies

I have some Cisco Cat2950LRE and 2950T switches in remote locations that I can only telnet to sporatically. If I reboot the switch, I can telnet to it about four times, but on the fifth telnet, the connection times out. This only happens if I'm telneting from a remote subnet; if



I'm on the same subnet as the switch, this problem doesn't happen.



This is what my con and vty settings look like:


! line con 0 session-timeout 5 timeout login response 300 privilege level 15 password 0 blahblahblah login line vty 0 4 session-timeout 5 timeout login response 300 privilege level 15 password 0 blahblahblah login transport input telnet line vty 5 15 session-timeout 5 timeout login response 300 privilege level 15 password 0 blahblahblah login transport input telnet !


I cannot figure out why telnet would quit working when coming from a remote subnet, but work OK for the local subnet. If it was a gateway problem, I shouldn't be able to telnet from the remote subnet at all. The fact that if fails after four succesful sessions led me to believe that the "session-timeout" and "timeout" commands should free up hung sessions, but that doesn't seem to be the case. And if that was the problem, it should apply to telnet sessions coming from the local subnet as well as remotely.


Am I missing anything? Thanks.



can't explain the difference between remote and local sessions however there are a couple of anomalies with your config.

This causes a session to stay up for 3 x 300 seconds when no successful login attempts are made. The default is 30 seconds.

I don't know what this does.

The default exec-timeout is 10 minutes I think.

I use:-

line vty 0 4 exec-timeout 60 0

In your case I would avoid increasing the exec timeout for now.

Consider applying an access lint to the vty(s).

access-list 23 permit 192.168.1.3 0.0.0.0

line vty 0 4 access-class 23 in

Note - TEST that you do not shut yourself out of remote systems when making these changes.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required