I cannot reach my SLES11SP2 host with ssh since a couple of days. Either with putty on win7 or ssh-command from other linux hosts - in both cases I receive "Permission denied (public key)".
ssh -v shows that authentication method "keyboard-interactive" is not offered anymore.
"debug1: Authentications that can continue: publickey"

The host runs as virtual machine on vmware esxi. The console of esxi is the only method to access the host at the moment. Configuration files like /etc/ssh/* and /etc/pam.d/sshd do not show any recent modification dates.

To get the issue resolved I decided to restore from a full backup older than my last successful ssh login. To my surprise the problem remained unchanged. Did someone experience a similar problem?

I already stopped ntp and manually turned back system time for 1 month - just in case it is a matter of expired functionality - but this didn't help.