[Mimedefang] MX -> 127.0.0.1

[Joseph Brennan]

--On Friday, September 9, 2005 5:51 PM -0500 Les Mikesell 
<les at futuresource.com> wrote:

> I think I've seen this mentioned before but can't find the answer.  I'm
> getting a bunch of spam where the sender MX ends up pointing to
> 127.0.0.1 or 0.0.0.0.  Is there a way to reject this quickly?  Not
> only is there the obvious problem of a bounce, but many of the
> destination users have moved and I'm forwarding to a box that does
> detect this problem but does a "450 Domain in reverse-path
> <chaifai at flashmail.net> resolves to an invalid IP address" temp_fail
> so even the ones with valid recipients are backing up in my queue.

We've been doing this for quite a while:

        if ($RelayHostname eq "localhost") {
            md_graphdefang_log('bounce',"PTR_to_localhost",$RelayAddr);
            action_bounce("You are not localhost");
            return action_discard();
        }

        if ($Helo eq "localhost") {
            md_graphdefang_log('bounce',"HELO_localhost",$RelayAddr);
            action_bounce("You are not me");
            return action_discard();
        }

Yesterday the first one rejected 1,257 and the second one 33,754.

Similar test for $Helo eq "128.59.48.6" (our IP address) got 13,969.

Joseph Brennan
Columbia University