fdqn hostname problem
I got a strange problem which I have been unable to resolve.
I have 2 servers.
* the first, server1.mydomain.com, runs an older fedora installation with qmail and plesk.
* the second, server2.mydomain.com runs brand new debian 5 with postfix and ISPconfig 3.
When I try to send emails from an address on server1 to an address on server2, the email gets rejected by postfix on server2 because of the policy "REJECT non_fdqn_hostname".
Now, I am puzzled as to why the hostname of server1 is non-fdqn.
The server sends a proper helo with server1.mydomain.com
Could someone please walk me through some steps to diagnose the problem?