MX records and spam reduction
After searching the forums, I can't find anything that addresses this. I have a mail gateway set up that's running Ubuntu/Spamassassin/Amavis/ClamAV and it's great. My MX records are something like:
1 - mail gateway
2 - Exchange mail server
50 - bogus mail server
I'm attempting to prevent some spam from accessing our Exchange box by working its way back up the MX records in reverse order.
Can I just as easily relist my mail gateway at a lower priority as well, like this?
1- mail gateway
5 - mail gateway
This way my SpamAssassin box will filter messages even from SMTP clients (spammers) that are going against the RFC and working up the MX list.
...and at this point I don't have the OK to take our Exchange server off the MX list totally - our SA install is too new to be trusted completely.