>
> In the folder .ssh there should be a file known_hosts. If there isn't
> maybe your ssh client does not have write to your directory.

Indeed, it was lacking.
I added the file via touch, but the problem remains the same


I also checked the permissions of .ssh:

drwx------ 2 giorgio users 48 2005-11-23 20:47 .ssh/

which should be correct.

Another
> possiblity it your trying to use ssh as root and it is set not to
> allow you which is a common security feature.

no, I am trying as normal user.