Unable to telnet into ASA

[Steve Coady]

Hello

I have an ASA5520. Up until recently, I was able to telnet into the device with no troubles.

I can access the command line via the ASDM.

I removed and re-entered the Telnet commnds, no success.

What could be causing this?

[Jouni Forss · Accepted solution]

Hi,

Can't say I ever had to troubleshoot Telnet connectivity to the ASA.

There is only one limitation that I know of that sometimes causes problems for people but this would mean that something would have changed in your setup.

The limitation that I mean is that if you ASA interface "security-level" value was 0 (if I remember correctly) then that interface wont accept Telnet connections unless you are using VPN connection to the ASA.

But somehow I doubt that this is causing your problem?

I would however suggest switching to use SSH to connect to the ASA. I would not use Telnet at all.

You could naturally capture the Telnet traffic on the ASA and see if that gives any clues. Does the ASDM show anything in the logs while you attempt the connection?

- Jouni