[Mailman-Users] MS Exchange as a relay computer?

Bob Puff@NLE bob at nleaudio.com
Wed Jan 29 06:46:45 CET 2003

Hi Alex,

> I have my Exchange setup to allow 500 recipients per message.  Mailman
> is also configured to send 500 recipients per message.  As a result
> all 55 aol.com, 65 yahoo.com, or 51 hotmail.com recipients on my
> largest list are send to Exchange on the same message.  Exchange can
> send a single message to handle all of those recipients instead of
> sending 5 or 10 as would occur when using the recommended batching of
> 10 recipients per message for postfix and other popular Unix-based
> MTAs.

Umm, no, that's the exact same way it works on any of my systems with Postfix.  I think I have one of my major mailing list machines currently set at 200, just to pick a

> Exchange 2000 has no problem sending the same message to multiple
> domains at the same time.  The remote deliver agent on most Unix MTAs
> can only send to one domain at a time so if you set the batching to
> 500 then you single thread your delivery and it can take forever for
> messages to get out.

Not true at all.  My mail servers connect to a ton of mail servers upon a message going out to a large list.  I'd say 50% of the messages get delivered within the first
couple minutes.  We're talking message counts in the thousands, and this is with somewhat small hardware (Celeron 500Mhz, 256MB RAM).

Although I've never messed directly with Exchange, other people's MS Exchange servers have caused me no end of grief, with them re-injecting mail, or incorrectly bouncing
it (with unparsable bounce messages).

Knowing a little bit about Windows, I'd bet if you stacked two machines side-by-side, a Exchange box and a Linux box running Postfix, identical hardware, and dumped a few
thousand messages on them (one server at a time), and measured the time it took to deliver the first 50%, you'd find the Linux box would have done it quicker, and used less
system resources.  It certainly would be an interesting test!

The summary is that I believe there is no benefit to running Exchange for a mailing list, and in fact, there are some potentially negatives for running it (security being
the biggest, compatibility being next).


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