VERY interesting David and nice idea. 
Chuck
-----Original Message-----
From: pctech-bounces@xxxxxxxxxxxx [mailto:pctech-bounces@xxxxxxxxxxxx] On
Behalf Of David Gibbs
Sent: Thursday, May 22, 2008 4:12 PM
To: PC Technical Discussion for iSeries Users
Subject: [PCTECH] Dummy backup MX
Folks:
I'm currently running an experiment with backup MX's.
I've always been of the opinion that some spammers will target a backup 
MX if one is available, with the assumption that the backup is less 
protected against spam & viruses than the primary.
As such, I've setup a backup MX for midrange.com and am running 
'smtptrapd' (
http://smtptrapd.sourceforge.net/) on it.
smtptrapd is a very small C program that listens on port 25 and always 
returns a 4xx soft error to the RCPT TO verb.
I setup the backup MX record in DNS about 2 hours ago ... and already 
I'm getting hit on it.  So far I haven't seen a single legit email show 
up on it.
Theoretically I could just have nothing listening at all on the backup 
MX system, but I want to see what tries to deliver to it.
david
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