Re: High volume mail handling architecture

[John Hedges <john@drystone.co.uk>]

On Fri, Sep 10, 2004 at 05:34:07PM +0000, Gerrit Pape wrote:
> On Fri, Sep 10, 2004 at 09:49:27AM +0200, Adrian 'Dagurashibanipal' von Bidder wrote:
> > Herre is what happens: A spammer uses my email address as the sender address 
> > in spam frequently.
> 
> > So, I sometimes suddenly have 2000 new mails in my inbox :-(
> 
> > So, that's my plea to everybody with big mail installations: make your 
> > frontend machines aware of what mail they are supposed to accept, so that 
> > you never need to bounce. (Ok, some cases will still bounce: disk full, 
> > procmail script errors etc., but these are a very small proportion.) And 
> > the other plea is, of course, get rid of qmail and other products which 
> > accept all mail by default.
> 
> As far as my experience goes, pleas or complaints against other people
> doesn't help much if you want to see something changed.  Better help
> yourself.
> 
> I suggest to instruct your mail user agent to make use of the
> (apparently almost forgotten) fact that the sender's addresses in the
> envelope and in the header can be different.  Most today's mail transfer
> agents should support address extensions.
> 
> If your address is used as envelope sender in unsolicited mail, it's
> your public one.  Use a non-public address as envelope sender of mail
> you send, and simply change it in case it gets abused; only bouncers
> should send mail to this address, and they usually do within two weeks.
> Now you can configure your MTA to outright reject delivery notifications
> solely based on the information in the envelope.
> 
> $ mconnect a.mx.smarden.org
> 220 smarden.org ESMTP
> mail from:<>
> 250 Sender accepted.
> rcpt to:<pape@smarden.org>
> 553 This address cannot get bounces, either you are not bouncing to the envelope sender, or the envelope of the mail you bounce is forged.
> quit
> 221 Good bye.
> $ 
> 
> I'm doing this for about ten months now, and don't see most of the
> unwanted delivery notifications, including delivery confirmation
> requests for unsolicited mail with forged envelope.

Sorry to reopen such an old thread. I'd saved this mail for reference as
I too get a lot of bounces for spam with forged mail headers. A fresh
run of spam that some wanker has initiated in my name has made my inbox
unbearable this last few days so I need to do something about it.

Would it be possible for you, Gerrit, to expand a little on your setup?
I currently use fetchmail to get my mail from a catchall mailbox at my
ISP. Can I use the envelope sender trick in this case as I can't see an
easy way to differentiate between bounces and normal email once the
messages reach my box?

Cheers

John