On Fri, May 03, 2002 at 11:09:53AM -0400, CertaintyTech - Ed Henderson wrote: | This question is not SA specific but just a general email sysadmin type | question: What is an effective way to monitor my own dialup customers to | see if any are abusing their email privilege by sending out spam? I am | using qmail. Somehow monitor the volume that each local IP is sending? Just | curious to see what others are using and how you do it.
First block outgoing connections to port 25. Your customers shouldn't
have their own mailserver, they should be using your smarhost relay.
Then require SMTP AUTH so you can track who really sent which message
in the face of forgery.
Then, at the very least, log all transactions so you can see who is
sending mail where and who they claim to be. It may (or may not) be a
good idea to verify that the sender address (MAIL FROM:) matches their
account with you.
-D
--
All a man's ways seem innocent to him,
but motives are weighed by the Lord.
Proverbs 16:2
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