[GRLUG] Sendmail as secondary (backup) MX

[Olding, Jim]

You could add a catch-all address in sendmail's virtusertable file, and
then set up a cron job to delete that user's mail file.

The downside of this is that anyone sending mail to that domain will
never receive a bounce message, even if they legitimately mistyped an
email address.

This also completely violates RFC 2821, which requires bounce messages
to be sent if your system accepts mail for delivery and later finds that
the address is invalid.

-----Original Message-----
From: grlug-bounces at grlug.org [mailto:grlug-bounces at grlug.org] On Behalf
Of Benjamin Eavey
Sent: Tuesday, October 31, 2006 10:36 AM
To: grlug at grlug.org
Subject: [GRLUG] Sendmail as secondary (backup) MX

Has anyone set this up and worked out all the kinks?  I have a machine
running Sendmail and acting as a backup MX for several domains. 
Everything has been working fine, for the most part, but now I'm running
into problems with the queue becoming overloaded.

It looks like a bunch of spam, and it appears to be a bunch of "550 -
undeliverable" messages and other similar stuff.  Looks like the
spammers are sending to non-existent addresses at the domains I host,
which are then bouncing with "undeliverable" messages, which are then
building up on my sendmail server, which is trying to deliver them to
the spoofed originating email addresses.

I know this is bad, and I'm pulling my hair trying to figure out how to
make this work properly, but I'm not getting anywhere.

Can anyone offer any suggestions?  Am I explaining this well enough that
the problem makes sense?

Thanks,

-Ben
_______________________________________________
grlug mailing list
grlug at grlug.org
http://shinobu.grlug.org/cgi-bin/mailman/listinfo/grlug