DNS::Email server needs to host my domain?.

[mikezp9]

Hello,

I've been unable to resolve an issue and need help.
I host DNS for a domain with a lot of records, call it domain.cxm. My company, which is of ISP size, has started a spam filtering service. So, now I have changed my DNS for domain.cxm from:
domain.cxm IN MX 10 server1.domain.cxm. ;customers email server
to
domain.cxm IN MX 10 spam.mydomain.cxm. ;spam filter at ISP

There are other domains with similiar zone records.
So, email is being sent to our spam box instead of the customers email server.
When the spam box does its thing, it has to send the email to the original mail server of the customer. Our spam admin. has setup the same domain on his spam box, but he needs his DNS to resovlve the MX for domain.cxm to the original email server, in this example server1.domain.cxm. This is working fine. The problem is that he only has the few nessessary MX and A records needed for the spam box to resolve the original records, so, when the spam box tries to resolve something.domain.cxm, the spam box returns NXDOMAIN, and, generates an error in the log file. I suggested that I send him the zone files I have for the domains. He doesn't want to do this because of the manual coordination that would be required between the DNS and spam boxes.
Is there a way for the spam box to query my DNS when it needs to resolve something that isn't in its zone file. Sorry for the long explanation, and thanks,
Mike

 

[skotman]

Mike,
what software are you using for your spambox? We ran IMgate (a postfix/FreeBSD solution) and our dns settings looked like:

domain.com      A  123.123.123.123
mail.domain.com A  123.123.123.456
domain.com      MX 10 spambox.ispdomain.com
mail.domain.com MX 10 spambox.ispdomain.com

domain.com      MX 20 mail.domain.com
mail.domain.com MX 20 mail.domain.com

On the spambox, we had an entry in the config file for each domain (I dont remember what the exact format is)

domain.com      123.123.123.456
mail.domain.com 123.123.123.456

this way, once the spambox was done with it, it knew where to foward the mail. The reason we have 4 MX entries is because if the spambox went down, mail would still be delivered.

Scott Heath

http://www.scottspad.com

AIM: orange7288

 

[jbud]

The solutions I'm familiar with are similar to what skotman describes.

Basically, the public MX records for the domain point to the spam filtering server. On the spam filtering server, there is a smart host entry for the domain in question that the spam filtering server uses to forward filtered mail.

Your spam administrator seems to be trying to do the same thing at the DNS/resolver level, rather than the MTA level.