Hi, my domain has a backup mail server, provided by an external company.   My MX DNS record looks like this:

Domain	Type	Class	TTL	Answer
mydomain.com.	MX	IN	900	mail.mydomain.com. [Preference = 10]
mydomain.com.	MX	IN	900	mail.companyx.com. [Preference = 90]

Along with the benefits of having a backup mail server, I'm noticing that it's also causing my domain to receive more spam that it otherwise would...

This is because when we receive incoming mail at mail.mydomain.com - it comes from two sources:

1. Directly from the SMTP server of the original server
2. Or relayed from the SMTP server of mail.companyx.com, assumably because my primary mail server was not available for some period of time.

 

When #2 is the case, the i.p. address that SpamFilter sees is a i.p. from companyx.com – not from the original sender.  I believe that messages relayed through the backup mail server cripple my ability to effectively scrutinize the messages with several of SpamFilter's important tools:  MAPS lists, i.p. blacklist, Honeypot i.p.s, SPF filtering, and the i.p. blacklist cache.

While my primary mail server runs nearly 100% of every day, most of the spam that my domain receives is through companyx's smtp servers that relay messages to my domain.

Does anyone have any suggestions?  I would love to have a way to scrutinize messages that are relayed by the backup mail server.
 

Thanks so much!

Stephen

Thanks, that sounds like a good setup.

I like the fact that my backup server is out of my office, but it certainly means that I don't have full control over it and it's junk mail policies.

Stephen