SPAM (on list) was:Re: classiccmp list (sort of) help requested

Cameron Kaiser spectre at floodgap.com
Fri Dec 15 13:01:56 CST 2006


> Also, it can be configured 
> to also verify the incoming addresses at the remote MX (which is likely 
> not the bot, thus it will discard such unauthorized sendings as well). I 
> use it at our central mail gateway with good success, as the vast 
> majority of valid mail severs meanwhile are RFC compliant.

I've been also being strict about forged hosts, i.e., when you do a reverse
lookup on the IP, and then forward lookup the reverse PTR, the IP should be
there. This has helped a lot, and doesn't impact the common situation where
a host (usually a home static IP) has a legitimate domain, but its PTR is
that of the network upstream (as long as that PTR resolves).

-- 
--------------------------------- personal: http://www.armory.com/~spectre/ ---
  Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com
-- Proponents of other opinions will be merrily beaten to a bloody pulp. ------



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