Mark McArthey <[EMAIL PROTECTED]> writes:

> I'm using fetchmail to temporarily pull mail from an old account, and this 
> spammer was able to get through by faking that old address.

Someday I need to read up on fetchmail to figure out just what it does
and what it's capable of doing.  I don't know it well at all, so the
following is based on some guesses of what it's doing.  This might not
work.

> I'd like to know if there's a rule I can use to avoid this specific
> problem in the future.  Thanks!

I'm guessing that fetchmail generates the envelope sender (when it
delivers through SMTP) from the From: field.  The Return-Path: field
in the email below looks to be generated by preline in your .qmail
file.

> Return-Path: <[EMAIL PROTECTED]>
[...]
> From: "jenna teddry" <[EMAIL PROTECTED]>

If you do not expect your local qmail to ever receive valid mail
*from* <[EMAIL PROTECTED]>, put that address in qmail's badmailfrom
file.  Then qmail will reject any mail that tries to use the
execpc.com address as an envelope sender.  If my guess about how
fetchmail generates the envelope sender is correct, this will stop all
mail with a From: field of <[EMAIL PROTECTED]>.  If you expect valid
mail with that From: field to be processed by fetchmail, don't do
this, as it will be rejected.

I don't know how fetchmail handles SMTP errors.  If it just gives up
forwarding all mail when it encounters an error, then this technique
won't work.  All I can suggest is that you put the address in
badmailfrom, send mail to the execpc.com account with a From: field of
<[EMAIL PROTECTED]>, send another, valid, email to that same account
and run fetchmail to see if the second gets delivered despite the
first being rejected.

Hope that helps,


Tim
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