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Community Member

Cannot telnet into router

What do I do when all of a sudden I can't telnet into my router through any interfaces?

I can ping the interfaces successfully, by IP and DNS name. Nothing has changed since the last successful login.

error msg:

Connecting To c3640...Could not open connection to the host, on port 23: Connect failed

3 REPLIES
Hall of Fame Super Gold

Re: Cannot telnet into router

The symptoms you describe sound like all the vty ports are in use. This may happen if you have configured the vty ports with no exec-timeout (or with exec-timeout 0 0 which is the same thing). If you can get to the console port the show user command (or the who command) should indicate which vty are in use - and I suspect that they all are.

If you can get to the console port and enable mode you could clear some of the sessions which would make telnet work again.

If you can not get to the console port you might wait and try later and see if it works after someone logs off. The other alternative is to reboot the router.

HTH

Rick

Community Member

Re: Cannot telnet into router

Rick,

Thanks for clarifying that.

I do have exec-timeout 0 0, but I still get kicked out of the telnet sessions if I'm idle too long.

Then the next thing I know, I've used up all the vty ports and can't telnet in.

In the past I'd just wait a day or two, but this time I can't get in for 4 days...looks like I'll have to get a laptop and console in...

Hall of Fame Super Gold

Re: Cannot telnet into router

Kevin

While I do sometimes configure the console with exec-timeout 0 0, I generally advocate not doig it on vty ports - mostly for the reason that you are experiencing. I sometimes put a very long timeout on the vty, but setting it to 0 makes me nervous.

Good luck with it.

HTH

Rick

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