SSH password authentication not working on virtual interface

On my linode running Debian 4, I have added a virtual interface eth0:1 but when trying to connect via ssh to the ip address on that new interface, password authentication does not work. It is not even one of the available methods. When connecting to the ip address of eth0 however, password authentication is one of the available methods and as expected it works.

Authentications methods on eth0:

publickey,password,keyboard-interactive

And on eth0:1:

publickey,keyboard-interactive

Interestingly, no logging occurs in /var/log/auth.log when connections are made eth0:1.

I tried changing to using PAM (ie UsePAM yes, ChallengeResponseAuthentication yes, PasswordAuthentication no) but that too did not work.

I'm stumped.

Any help would be much appreciated.