[Mimedefang] $RelayHostname not matchingsendmail's Receivedheader?

[Jan-Pieter Cornet]

On Wed, Dec 06, 2006 at 11:32:57AM -0800, John Rudd wrote:
> Botnet looks to verify that:
> 
> a) the relay has a PTR record at all
> b) optional: the hostname in the PTR record resolves, and resolves back 
> to the IP address that you're talking to
> c) the hostname doesn't contain 2 or more octets of its IP address in 
> hex or decimal form
> d) the hostname doesn't contain certain "client like" keywords (dsl, 
> dynamic, dialup, etc.)
> e) (in Botnet, but not in my mimedefang version) will exempt c & d if 
> the hostname does contain certain "sever like" keywords.

I might test your Botnet plugin, but I'd make a few additional exemptions
that were suggested on the spamtools mailinglist. If either the HELO or
the envelope sender domain points back at the sending IP, it is
also allowed. Unless, of course, either of those are generic rDNS
or [] bracketed IP constructs.

The idea is that SMEs on crappy DSL lines that do not allow you to
change reverse DNS, but that do operate their own domain, properly
pointing back to their own mailserver on their DSL line, are allowed
through.

I'll even patch that myself if I can find a round tuit, and install
it for my test-userbase.

-- 
Jan-Pieter Cornet <johnpc at xs4all.nl>
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