[exim] ot: rDNS + spam assassin

Hi everyone,

I hope its ok to ask an off topic question in this group. I ask here
because even though it is off topic its obviously closely related and
I'd love to hear what your thoughts are on the following:

In my exim servers I assign a very high spam assassin score to incoming
mail servers without rDNS (RDNS_NONE = 4.5).

This has worked well for me blocking a fair amount of spam (or rather,
pushing the overall score high enough to block the spam).

I have a client on my servers who cannot receive mail from one of their
contacts. It turns out that this sender's forward and reverse records
don't match exactly, eg:

mailsecurity-01.example.com. => 1.2.3.4

but

dig -x 1.2.3.4 => gateway.example.com.


So my question(s) are basically:

1) am I being too over the top assigning such high spam assassin to
incoming mail without valid rDNS?

2) Should it be considered valid if the tld matches but not the sub
domain as in the example above (and if so any pointers on how to achieve
that in exim)?


Thank you,

John McMurray

john@???