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Step-by-Step Configuration and Troubleshooting Best Practices for the NGFW, NGIPS and AMP Technologies A Visual Guide to the Cisco Firepower Threat Defense (FTD)
Community Member

SSH stopped working


i encounter the problem not be able to ssh to my ASA5510 anymore. the log shows a entry with "Resource 'ssh' limit of 5 reached for context 'single_vf'". i found already some posts on the internet stating to regenerate the rsa key. i did it with "crypto key generate rsa modulus 1024", but this didn't helped a bit. i'm still getting the error in the log and not able to ssh to it. i found a post saying to 'zeroize rsa' first, but i have no idea how to do that. any suggestions?



Re: SSH stopped working

The only way I've been able to SSH again is to reboot the firewall. I've been waiting for it to happen again so I can open a TAC case. Maybe you could do that and let's us know what Cisco says?

Community Member

Re: SSH stopped working


I think I've had this happen to me before, and I think rebuilding the keys worked. I believe that on 6.3 the syntax is "ca zeroize rsa". I don't see it in the command reference document for 7.2, but that doesn't mean it's not there. Hope it works for you.

Re: SSH stopped working


To remove the keys on an ASA device.

ASAOne(config)# crypto key zeroize rsa default

WARNING: The default key pair will be removed

WARNING: All device certs issued using these keys will also be removed and

the associated trustpoints may not function correctly.

Do you really want to remove these keys? [yes/no]: yes


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