Cisco-Education wrote: <snip>
Jun 19 16:26:06 kmdns1 sshd[11073]: Invalid user jeka from 87.118.122.78 Jun 19 16:26:06 kmdns1 sshd[11074]: input_userauth_request: invalid user jeka Jun 19 16:26:06 kmdns1 sshd[11074]: Received disconnect from 87.118.122.78: 11: Bye Bye
<snip>
Now both the Mail server and the backup pc server behind firewall and ssh protocol is denied to the hosts in the DMZ zone
doesn't look like it :-) check your firewall, ssh is definitely getting through to that mail server.