Date: Tue, 08 Apr 2003 17:42:07 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Dan Langille <dan@langille.org> Cc: freebsd-chat@freebsd.org Subject: Re: foo+bar@ addresses, procmail, and postfix Message-ID: <3E936C5F.33549B1@mindspring.com> References: <3E930CA5.30714.112296A7@localhost>
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Dan Langille wrote:
> I'm trying to get foo+bar@example.org addresses to work with
> procmail. My MTA is postfix. I've had a hard time tracking down the
> information and trial and error has gotten me a working solution.
> I'm wondering if there is a better way to accomplish this[1].
You should look at the "Cyrus" mailer.
For "plussed" addresses, your MTA/MDA should not consider the
portion following the "+" as part of the local address, when
doing local address validation, user validation, account
validation, etc.. But it should pass the portion following
the "+" to the MDA/local delivery agent, IFF the local delivery
agent understands "plussed" addresses. The Cyrus "deliver"
program (the MDA that comes with the Cyrus distribution) takes
that portion as an additional command line argument, in the
normal case.
I don't know what procmail is/isn't willing to take as additional
command line arguments (normally, I use Sieve, not procmail, so
that I can automatically direct the mail to a specific IMAP4
mailbox as a result of the plussed addresses and/or Bayesian
filtering, etc., without giving users the ability to run code
on my systems), but you could always stuff it in the environment
before invoking procmail, if that was the only way to get procmail
to see it.
But either way, you need to modify the MDA invocation by the MTA,
on local delivery.
I can tell you how to do this with sendmail ("Look at the Cyrus
mailer!" 8-)), but I don't know the answer for Postfix or Qmail,
or if it's even possible (Sendmail is cool! 8-) 8-)).
> This type of addressing is often referred to as address extensions.
> I found one clue at http://pm-doc.sourceforge.net/pm-tips-
> body.html#using_plus_addressing_foobar. My problem was that I could
> not get the "bar" bit of the address. But the above URL mentions:
That's because mail.local doesn't take or pass on optional
arguments to programs invoked in .forward files. It's an
MDA that doesn't support that.
There are "mail.local" replacements available on the net,
but if you use them, you need to replace the MTA/MDA interface,
since it expects to be able to send to multiple local users,
simultaneously. The normal way to disable multiple users
simultaneously in sendmail is to remove the "m" flag on the
"local" mailer.
> Any comments? Ideas? Improvements?
Don't run procmail globally. Replace your mail.local, if you
need to, but don't run procmail globally.
> [1] - with the tools mentioned. Those suggesting a change of MTA
> will be beaten to death with spam.
I suspect you can do this with Postfix, but I'll be damned if
I know the dead chicken you would have to wave for it to work.
If Postfix actually supports Cyrus IMAP4, rather than just
pretending to support it, then "however you have to configure
Postfix for Cyrus plussed mailboxes" is the correct answer.
-- Terry
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