RE: Mail Relaying

Jon,

Set your SMTP to only allow relaying from your local network (probably
10.x.x.x or 192.168.x.x).  Nobody else can use it.

Then, when you are on the road, use your ISP's SMTP, but use the POP server
on your AS/400 (or whatever you use when in the office).

Bob Crothers

-----Original Message-----
From: owner-midrange-l@midrange.com [mailto:owner-midrange-l@midrange.com]On
Behalf Of Jon.Paris@hal.it
Sent: Thursday, April 12, 2001 4:19 PM
To: midrange-l@midrange.com
Subject: Mail Relaying

A prolonged period of frantic activity on our mail server (V4R4) last night
(80% + CPU!) led us to wonder if we were being used for relaying.  We
tested and sure enough we were wide open.  We have set things up as per
IBM's PTF cover letter on the subject but either I'm misunderstanding or I
have a problem with IBM's implementation.  I'm hoping someone can set me
straight.

In order to block relaying you either have to specify which IPs cannot
relay (not practical) or specify all those IPs which can.  This is the
approach we have used but there is a problem.  Several of our users travel
(me for one!) and often use e-mail from home or on the road.  I wouldn't
have thought connecting as an e-mail client counted as relaying but it
seems to.  Of course these users have a different IP each time they
connect.  In order to make it work the way I understand it, we'd have to
shut down the server - add the current IP and restart the server.  This
just isn't viable - so I'm hoping that I've missed something somewhere.

Can anyone enlighten me?

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