Hello!
I am currently working through an issue with outbound email, and was curious what solutions are out there.
Basically, we have IronPort behind a ASA relaying email. The ASA has 2 ISP's used for redundancy purposes.
ISP1 --> mail.example.com
ISP2 --> mail2.example.com
mx records --> pref 10 mail.exmaple.com
--> pref 20 mail2.example.com
IronPort Interface hostname --> mail.example.com
When the main ISP is up, everything is happy.
IronPort's interface is configured with the hostname mail.example.com, which in turn, is populated into the SMTP banner. Reverse DNS checks of course pass.
The issue is if ISP1 fails, and email starts getting sent out ISP2 (mail2.example.com)
IronPort still populates the SMTP banner with mail.example.com, Resulting in reverse DNS checks failing.
My 2 questions are basically.
1) Is there a solution to deal with this? Have IronPort send out mail2.example.com in the event of a failure?
2) If no, does this even matter? Obviously its undesirable, but according to the RFC, email servers should not actually be blocking email based on this fact.
Thanks in advance!
