topic Unable to SSH from Outside to ASA 5520 in Network Security

Unable to SSH from Outside to ASA 5520

Pratik Prajapati — Mon, 11 Mar 2019 22:27:00 GMT

I am unable to ssh to the cisco firewall from outside. Though when i telnet on port 22, i do get a reply Please see below.

Below is my config

aaa authentication ssh console LOCAL

ssh 0.0.0.0 0.0.0.0 inside

ssh 0.0.0.0 0.0.0.0 outside

ssh timeout 5

console timeout 0

When i do a putty session i get a blank screen. Not sure why is it happening.

Unable to SSH from Outside to ASA 5520

Kimberly Adams — Thu, 09 Feb 2012 18:45:32 GMT

Try adding the specific networks that are allowed to ssh to the inside and outside of your ASA.

Thanks,

Kimberly

Unable to SSH from Outside to ASA 5520

tahequivoice — Thu, 09 Feb 2012 18:50:28 GMT

Did you generate the RSA key? I find myself forgetting that one stinking thing and get locked out since I only use SSH.

cry key gen rsa mod 2048

Unable to SSH from Outside to ASA 5520

Pratik Prajapati — Thu, 09 Feb 2012 18:55:00 GMT

I did generate RSA key but i used 1024.

Also ssh works from inside. Only outside is the problem.

I tried adding specific networks too but no luck.

Unable to SSH from Outside to ASA 5520

ahmad82pkn — Thu, 09 Feb 2012 18:56:13 GMT

any ACL on outside interface?

Unable to SSH from Outside to ASA 5520

varrao — Thu, 09 Feb 2012 19:03:36 GMT

Plz check if port 22 is used on the outside interface for any other service...

Chcek "show asp table socket".

Thanks,

Varun

Unable to SSH from Outside to ASA 5520

Pratik Prajapati — Thu, 09 Feb 2012 19:11:30 GMT

below is the output of 'show asp table socket'

Protocol Socket Local Address Foreign Address State

SSL 0000a73f 192.168.6.1:443 0.0.0.0:* LISTEN

TCP 0ad7604f 192.168.7.1:22 0.0.0.0:* LISTEN

TCP 0ad7a17f 204.138.112.2:22 0.0.0.0:* LISTEN

TCP 0ad7d1ef 192.168.6.1:23 0.0.0.0:* LISTEN

TCP 0ad85148 192.168.7.1:22 192.168.7.10:49964 ESTAB

Unable to SSH from Outside to ASA 5520

tahequivoice — Thu, 09 Feb 2012 19:14:42 GMT

What version IOS is it running and how long has it been up? There are a couple versions out that have an issue with SSH that I ran into that show this problem, a reboot normally clears it up.

Unable to SSH from Outside to ASA 5520

varrao — Thu, 09 Feb 2012 19:19:06 GMT

Yes, a reboot might help or remove the outside interface ssh configuration, zeroise the crypto keys, the generate the rsa keys again and re-add the ssh outisde interface configuration.

Thanks,

Varun

Unable to SSH from Outside to ASA 5520

Pratik Prajapati — Tue, 14 Feb 2012 17:57:01 GMT

This is funny. We had a crypto map for some reason for that network thats why i wasnt able to do an ssh. but it works now. Thanks Guys.