> The only thing I am really concerned about is whether there will be
> problems with the "hop count". We have ours set to thirty, but there are
> still a lot of servers which won't accept mail after it's been through
> seventeen systems or more before reaching the destination [this is to
> prevent mailing loops].

If you do the forwarding by setting the SMTP_FORWARD variable in the
configuration file, it doesn't add hops at all -- the mail server
will show up as the first hop. Your mail server will also need to
support forwarding from another host for this to work correctly.

That said, you'd better be prepared to throw a lot of disk and RAM at
your central mail server _immediately_ -- most Unix systems think a
heavy load is 10-15K messages a day, and a good campus LISTSERV can
easily top out at several times that.  You may also have to disable
some features (like reverse IP address lookups on incoming messages)
that your security people require to get reasonable performance for
LISTSERV.

> So, my main question would be "does anyone know a nice way with sendmail
> to have it deliver to host x, y, and z; and everything else should be sent
> to a mail hub for delivery". That way I could tell the mail system to
> deliver mail directly to the LISTSERV backbone hosts, and give the rest of
> the stuff to the powerhouse mail hub.

Well, the simple answer is to get a copy of LSMTP and a medium sized
NT box and point LISTSERV at that for it's delivery engine. This
costs money, but is eminently fast and elegant.  There are delivery
rules files in LSMTP that allow you to point mail for specific hosts
to specific locations and default for everything else.

> Would I be likely to push mail systems over the edge if I just
> forwarded everything to the main hub?

Other than additional load on the hub, probably not. Most of the
really pathological mail systems are now behind more modern stuff
that caters to them.
David Boyes
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