Use procmail to deliver to stdout and a second server

Question

I would like a Postfix server to deliver each message to a certain transport as well as relay to a second server. In master.cf, I have the following transport:

zarafa unix - n n - 10 pipe
  flags= user=vmail argv=/usr/bin/zarafa-dagent ${user}

Because I can't get Postfix to deliver to two transports, what I probably need, is a wrapper transport, using procmail maybe, that delivers to zarafa-dagent and relays to a second server (not just forward to an address; relay to a second server).

It can also be a script that calls sendmail or whatever, but at the moment, I don't know how to proceed.

things like bcc_maps don't work, because then it doesn't produce corrent X-Original-To and Delivered-To headers. It needs to be sent to the same recipient on the the server it's being relayed to as the original server.

Edit: maybe I should clarify something: on the backup machine, I can't have the same mailboxes as the primary; there's just one box. If I did have all the mailboxes, a BCC to that server would be fine. But because on the primary, e-mail is delivered using custom zarafa transport, there is no way I can let the secondary know what mailboxes there are. Hence I wanted to relay to that server, and that server also considers itself local for the domain in question. That way, Delivered-To header would tell me what the original RCTP to was.

Answer 1

With the help this page, I think I'm almost there, but not yet. I don't know how to relay to the second server yet, from bash.

I made a transport in master.cf:

filtertest    unix  -       n       n       -       10      pipe
    flags=Rq user=filter null_sender=
    argv=/usr/local/bin/filter-test.sh -f ${sender} -- ${recipient}

I included the content_filter option to the smtp transport (will add it to smtps too when it works):

smtp      inet  n       -       -       -       -       smtpd
    -o content_filter=filtertest:dummy

I have the filtertest script:

#!/bin/bash

# Simple shell-based filter. It is meant to be invoked as follows:
#       /path/to/script -f sender recipients...

# Localize these. The -G option does nothing before Postfix 2.3.
INSPECT_DIR=/var/spool/filter
SENDMAIL="/usr/sbin/sendmail -G -i" # NEVER NEVER NEVER use "-t" here.

# Exit codes from <sysexits.h>
EX_TEMPFAIL=75
EX_UNAVAILABLE=69

# Clean up when done or when aborting.
trap "rm -f in.$$" 0 1 2 3 15

# Start processing.
cd $INSPECT_DIR || {
    echo $INSPECT_DIR does not exist; exit $EX_TEMPFAIL; }

cat >in.$$ || {
    echo Cannot save mail to file; exit $EX_TEMPFAIL; }

# Relay message to backup server
#TODO: how?

$SENDMAIL "$@" <in.$$

exit $?

What remains is: how do I make this bash script relay (not forward) the contents of the tmp file to a second server?

Answer 2

I needed to do something similar, and about your question it really seems postfix doesn't allow for more than one delivery at a time.
The way I managed to solve my problem is to use a little wrapper to catch the request and then run the needed dispatches.
The only problem with it is that postfix will say "Okay, delivered!", but it doesn't really knows if the delivery has been successful or not.
Anyway, this is my wrapper's code:

#!/bin/bash
USER=`echo $2 | awk -F"@" '{print $1}'`
NEXTHOP=`echo $2 | awk -F"@" '{print $2}'`
/usr/bin/sudo -u vmail /usr/bin/procmail -t -m USER=$USER NEXTHOP=$NEXTHOP /etc/procmailrc

"USER" is the username contained into the email, "NEXTHOP" is the domain contained into the email... to be clear: USER@NEXTHOP.

The message would then be passed as stdin to the script, allowing you to fetch it and to use at your own discreption.

I just hope it would be useful to you :)

Answer 3

You can try and use roundhouse or install MIMEDefang and use add_recipient to relay emails to any other server you want.