We've been running MS's SMTP service for store and forwarding for several
months now with great success.  However, we've come under quite a few
distributed dictionary attacks over the last few days, and this is creating
a problem.

I have the MS SMTP service set to deliver all messages through to our IMail
machine, and not to attempt delivery itself.  This creates the disasterous
situation that MS-SMTP requeues dictionary attack messages and tries to send
them out, and then rather than reject them itself, sends the rejections on
to the IMail server for final delivery.  This effectively doubles the
traffic load from these attacks.

What I want to do is change the setting to allow the MS-SMTP server to
deliver the messages itself.  Thus if it tries to pass on a message with an
invalid email address to the IMail server, the IMail server will reject it
and then the MS-SMTP server can turn around and attempt delivery of the
rejection itself.  Since the overwhelming majority of these messages are
forged anyways, I can wipe out the badmail directory every few hours, and
I'm not pushing crap messages across my LAN and keeping my IMail server busy
dealing with another SMTP server's rejects on top of its own.

Does anyone see a problem with this?

-- 
Aaron Clausen
[EMAIL PROTECTED]


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