SA gateway

[Maxim Černý <ma...@czerny.cz>]

Hello,

I've set up working spam filtering gateway using amavisd-new and spamassassin. It's working great, 
most of spam messages are spam-tagged. The problem is that I have domain example.com which is 
suffering from spam messages. I changed the MX dns record from mail.example.com to 
spamfilter.example.com. So when somebody want to send mail to user@example.com the mail goes 
to spamfilter.example.com(there is SA) and then (postfix transport) to mail.example.com where it is stored. 

Well, it works with regular mail, but the spam-robots keeps sending spam messages directly to 
mail.example.com, so I can't filter them on spamfilter.example.com.

Do they have some memory where is stored "if i'm sending mail to example.com, don't ask for MX record 
for that domain, but send it directly to mail.example.com"? 

Is there any solution to fight this? I can't install SA on mail.example.com.

Thank you for answer

M. Cerny