A.P. Lawrence

Unknown email user notification

Mon Jul 26 15:04:52 2004 Unknown email user notification
Posted by Tony Lawrence
Search Keys: mail,spam
Referencing: /Blog/B868.html

As nice as it is to notify people that they may have mis-typed an email address, the current spam climate makes that polite response a bad idea. It's better to just silently throw the messages away. Notifying the spammer either lets them know that you exist or just clogs up your mail queue with undeliverable messages because their return address is bogus.

There are a number of ways to handle that. See SME server virus scan notification and double bounce if you are using SME. If you control your mail server, you may have a way to silently ignore such mail. Sendmail defaults to that behavior, but if you have multiple domains, etc. it may not be doing that.

If your mail server no other way to do this, you may have a "catch-all" account you can direct to a specific user. Unknown users will then go to that account. You can put rules into your mail client that just silently delete all mail that comes there. That effectively prevents any notification, so that helps mailserver congestion, but it still means all those messages have to be downloaded. Better that than nothing, though.

Comments /Blog/B1016.html
CommentsBlog1016 :

"If your mail server no other way to do this, you may have a 'catch-all' account you can direct to a specific user."

There's always /dev/null. <Smile>

--BigDumbDinosaur

---July 26, 2004

Well, that's excatly where it ends up with the SME patch. You were kidding, but because of the way qmail works (accepting mail before it expands aliases), that's what we actually do.

On my BSD server, I have to use a catchall account (if I don't, "no such user" messages are sent), and that has to go to another mail address. So I make that "foofoo" at my SME server, which then throws it away. Annoying series of steps (though no involvement after setting it up, of course) and a waste of bandwidth, but that's what I have to do.

--TonyLawrence

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