Resolved! Outbound PAT for SMTP traffic
Cisco ASA 5505, Software 8.0(3)ASA IP: xxx.xxx.xxx.yy4/29This is part of my ASA config that ensures PAT for incomming SMTP traffic:access-list acl_inbound_outside extended permit tcp any host xxx.xxx.xxx.yy7 eq smtpnat-controlglobal (outside) 1 inter...