We recently bought so new Firewalls to replace to aged Cisco PIX515e with some new Gear. We decided to use Ciscos new Firewall flagship the Cisco ASA Devices. Everything was fine after the replacement, we transfered the configuration from the old boxes to the new with the help of the Cisco Security Manager.
Later that day there was complains about e-mails are not delivered properly.
On the Cisco PIX with Software 6.2 we had implemented following:
no fixup smtp
For the ASA5510 we had to implement following
policy-map type inspect esmtp esmtp_pmap parameters allow-tls action log policy-map global_policy class inspection_default no inspect esmtp inspect esmtp esmtp_pmap exit exit