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

On Tuesday, February 01, 2005 at 06:31 CET,
Daemeon Reiydelle <daemeon.reiydelle@anthros.com> wrote:

> 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:=20
> <foo>.mailrelay.org as a Receipt: stanza "above" to all the spammer jun=
k.

Yes, backup MXes are quite overrated these days.

> What is happening is that spammers are sending emails to ALL of the mx=20
> hosts (even when the lowest preference is up) so I get:
>=20
> Receipt: host26.mailrelay.org
> Receipt: some.spammer.jp
>=20
> Obviously the mailrelay.org entry is the sender, and that is not RBL'ed=
..
>=20
> What I want to do is to check each Receipt: line against my=20
> favorite RBL's, at least for Receipt: lines subsequent to
> mailrelay.org if the email came from *.mailrelay.org.
>=20
> 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?

Yes, use a content filter. SpamAssassin is one example of such that
parses Received lines and performs DNSBL lookups.

Drop the backup MX service. If you really need it, you shouldn't be
running an MTA in the first place.

[...]

--=20
Magnus B=E4ck
magnus@dsek.lth.se