One for Mr Grumpy…
In the likely event that you upgrade a FWSM or possibly some other similar hardware. It seems that during the upgrade process it kills your SSH configuration and you need to regenerate the keys. This can be achieved with a simple “crypto key generate rsa”. However, if you run a linux management system then you may need to delete and reset the key on the linux host for the remote node your attempting to access..
sudo ssh-keygen -f “/var/lib/<user>/.ssh/known_hosts” -R <ip-address>
where <user> is the user such as root on the local linux host and <ip-address> is the address of the host your connecting to. An example to remove the key from the local user is:
ssh-keygen -f “/home/network/.ssh/known_hosts” -R 188.8.131.52