On my primary I have an ACL to verify the recipient and if this fails refuse to accept
which results in a '550 unknown user' being sent. This is standard, fine and works well.
My MX secondary receives it's share of username-generation spam attacks, when it tries
to forward this cr*p onto my primary, the primary bounces them (see above).
The problem is that my MX secondary holds onto these and retries, this fills up
the mailq, etc.
How can I get the MX secondary to bounce (or preferably discard) such mail ?
I have considered putting a list of users on my MX secondary and doing a check at RCPT
time, but would rather avoid that: extra work maintaining the list, ...
I need to be careful to distinguish 'unknown user' from other 550, such as over quota/...
TIA
--
Alain Williams
Parliament Hill Computers Ltd.
Linux Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer.
+44 (0) 787 668 0256
http://www.phcomp.co.uk/
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