How to check each Received: line against RBL's?

I recently had a service that provides backup MX services in case my
servers are down. Basically their service appears useless as, to my
domain, they appear to be an open relay, adding Receipt: <foo>.mailrelay.org as a
Receipt: stanza "above" to all the spammer junk.

What is happening is that spammers are sending emails to ALL of the mx
hosts (even when the lowest preference is up) so I get:

Receipt: host26.mailrelay.org
Receipt: some.spammer.jp

Obviously the mailrelay.org entry is the sender, and that is not RBL'ed.

What I want to do is to check each Receipt: line against my
favorite RBL's, at least for Receipt: lines subsequent to mailrelay.org if the email came from *.mailrelay.org.

Is there a way to parse each Receipt: stanza against RBL's in an if statement such that the rhs of the Receipt:
is passed to an RBL lookup program?

I currently do header checks, but I need to invoke a process (?) in the right hand side of the pattern match.


I currently do RBL validation, but that only works for the sender (in this case foo.mailrelay.org) when they connect
to my domain. It's OK to take up the overhead to do these checks although annoying that spammers are hitting ALL of
the MX records.

PS. does anyone know of any backup MX services besides DynDNS, ideal one that does RBL checks?



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Daemeon Reiydelle



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Daemeon Reiydelle
(USA, GMT-8 hrs.) +01.510.231.0880




--


Daemeon Reiydelle
(USA, GMT-8 hrs.) +01.510.231.0880