We have 2 ASA 5505 devices used to create a VPN to a client. Whilst there are 2 ASAs, only one is used at any time; the other is configured identially as a hardware backup.
Their startup-config files only differ in the hostname.
Remote SSH access to the ASA from several static IP addresses has been enabled on the outside interface. We can connect succssfully via SSH from a remote IP when one of them is used, but when it's replaced with the backup ASA, attempting to SSH to it results in the message "Server unexpectedly closed network connection".
SSHing to either ASA works fine via the inside interface.
The boxes are outside our firewall, and so traffic to it isn't being restricted by that.
Can anyone please suggest what might be causing this? Thanks for your help.
Please double check if you have allowed access for your IP address:
ssh a.b.c.d 255.255.255.255 outside
assuming a.b.c.d is your IP address. Also, do you have "aaa authen ssh console LOCAL" and rsa keys generated "show crypto key mypubkey rsa".
Please paste the logs you get on that ASA when trying to SSH to it.