[TriLUG] Postfix v QMail ?

[Tanner Lovelace]

On 6/21/05, Christopher L Merrill <chris at webperformanceinc.com> wrote:
> That's an interesting way to identify spam, but does it help you
> reduce the spam at all?  Is there any way to "revoke" an address
> you have given out?  In other words, once somebody starts spamming
> on an address you have given out, can you disable that address?
> 
> I ask because I've been doing a similar thing for 2 years now using
> an aliases file in Postfix.  I started this as an experiment to find
> out if any vendors I deal with were selling their e-mail address
> database (apparently, most do not).  Making an entry in the aliases
> file every time I need a new address can be cumbersome, but has the
> advantage of being able to "revoke" the address at a later date.

Yes, you can revoke these addresses.  I do it this way.  In /etc/postfix/main.cf
under smtpd_recipient_restrictions I add the following line (along with some
other stuff I'm not showing to make things more clear)

smtpd_recipient_restrictions =
        check_recipient_access hash:/etc/postfix/access-inbound

Then in the file /etc/postfix/access-inbound (which could be named anything)
I put this:

lovelace-oktest at wayfarer.org    REJECT

I can put any more addresses that I want to reject in access-inbound
and it will work just as you expect.

Note, btw, that you can put other addresses there also.  For instance,
I also have this there:

postmaster at wayfarer.org         OK
hostmaster at wayfarer.org         OK
abuse at wayfarer.org              OK
insurance at wayfarer.org          REJECT Wayfarer.org doesn't deal with
insurance.  Check your address.

Note on the last one you can give a reason for the rejection that will be shown
when postfix rejects the e-mail.  You can also use DISCARD instead of REJECT
but that's not recommended because it silently discards e-mail without any
notice to anyone.  REJECT at least lets the sending MTA know there's an
error.

That's actually another thing I prefer about postfix over qmail.  When qmail
wants to reject an e-mail it accepts the e-mail and then generates a rejection
bounce.  That is incorrect in every sense of how things should be.  Postfix,
on the other hand, can reject as the mail is coming in, before accepting the
e-mail.  This reduces the number of spurious bounces (because if an e-mail
is forged, qmail will bounce it back to the forged address while postfix, by
rejecting before receiving, will not).

Cheers,
Tanner

-- 
Tanner Lovelace
clubjuggler at gmail dot com
http://wtl.wayfarer.org/
http://www.freeiPods.com/?r=8127171
(fieldless) In fess two roundels in pale, a billet fesswise and an
increscent, all sable.