As of last Friday, we can not recieve email from one company (that we know of). I don't remember making any changes to the firewall except adding pptp to the inpection list. I have removed ESMTP from the inspection list and still can't recieve their email.
This is what I see in my logs:
Jun 16 2008 13:55:48: %ASA-6-302013: Built inbound TCP connection 1969454 for Outside:18.104.22.168/11877 (22.214.171.124/11877) to DMZ:SpamFW/25
generic_num=6, specificTrap_num=1, specificTrap_name=, clogHistFacility.0=20, clogHistSeverity.0=7, clogHistMsgName.0="Syslog Trap", clogHistMsgText.0="<166>Jun 16 2008 13:55:48: %ASA-6-302013: Built inbound TCP connection 1969454 for Outside:126.96.36.199/11877 (188.8.131.52/11877) to DMZ:SpamFW/25 (184.108.40.206/25)", clogHistTimestamp.0=69394600
Jun 16 2008 13:55:48: %ASA-6-302014: Teardown TCP connection 1969454 for Outside:220.127.116.11/11877 to DMZ:SpamFW/25 duration 0:00:00 bytes 0 TCP Reset-O
Thanks for your reply, but it ended up being a problem with the sender. They did not tell me they were having other mail related issues and just decided to blame us. The 18.104.22.168 address was their sending mail host, and it would send an immediate reset after establishing the connection.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...