cisco pix and ssh key troubles….

Have you ever received the following when you were trying to ssh into a Cisco PIX or ASA?

ssh_rsa_verify: RSA modulus too small: 512 < minimum 768 bits
key_verify failed for server_host_key

Then you may find the following Cisco commands handy to remember…

To examine the device’s currently installed ssh key.
sh crypto key mypubkey rsa

To reset the key to zero.
crypto key zeroize rsa

Finally to generate a new key of an appropriate length.
crypto key generate rsa modulus 1024 noconfirm

I hope this helps someone out there.

m