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starfry
Asked: 2013-03-21 07:26:13 +0800 CST

how to configure postfix to send local mail to another local server?

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I have a pair of mail servers that are comprised mainly of Postfix, Procmail and Cyrus-IMAP and they both work fine. The IMAP servers are configured in a simple master/replica pair. All 'normal' mail is accepted by the master's Postfix which processes it through Procmail for delivery to the Cyrus-IMAP running on the same server. Both servers are capable of running like this but only the master actually receives external email.

At present, local accounts on either box send mail (for example, generated by cron jobs) through its local Postfix which is delivered locally to the Cyrus-IMAP on the same box.

However, Cyrus's replication doesn't like changes happening directly on the replica so I would prefer for the replica to deliver its local mail to be delivered to the master.

I see two ways of achieving this:

  • change the replica's local transport to deliver mail to Postfix on the master server

or

  • change the replica's procmail to deliver mail to Cyrus-IMAP on the master server.

There is a third way which is for the replica server to relay everything to the master server (i.e. both internal and external emails) but that seems somewhat unnecessary. I don't need to change how external mail is handled - it's ok for either box to send external email via its local Postfix which then relays it externally.

What I really would like to do is just change how internal emails are processed on the replica so that it delivers them to the master, either into Postfix or into the IMAP server there.

Existing, working, configuration of my local transport in postfix's master.cf:

procmail-local  unix  -       n       n       -       -       pipe
    flags=OR user=cyrus argv=/usr/bin/procmail -t -m RECIPIENT=${mailbox}
    SENDER=${sender} EXTENSION=${extension} /etc/procmailrc

Existing, working, configuration of delivery to Cyrus in procmailrc:

DELIVERMAIL="/usr/lib/cyrus/bin/deliver -r $SENDER -a $RECIPIENT $RECIPIENT
postfix

3 Answers

  1. Best Answer

    I'd do it earlier still - by removing your domain name from mydestination, mail for that domain should be delivered to the server listed as MX for your domain. If you want to specify a server, as opposed to using the MX, you should use the file /path/to/postfix/etc/transport for this. That file should then look like this:

    # all mails to our own domain should go to our main incoming server
ourdomain.com    smtp:[mainserver.ourdomain.com]

    Please note that the [] marks are important - without them, your server will still lookup the MX record for mainserver.ourdomain.com.

    After editing the file, use the command postmap /path/to/postfix/etc/transport

    You also need to make sure that postfix knows to use that file, by editing /path/to/postfix/etc/main.cf with the following line:

    transport_maps = hash:/path/to/postfix/etc/transport

    if your system uses db files. If instead it uses dbm files, the line should be

    transport_maps = dbm:/path/to/postfix/etc/transport
    • 7

  2. You could try using transport_maps, on the replica you put in main.cf 

    transport_maps = hash:/etc/postfix/transport

    then in /etc/postfix/transport you put

    localdomain smtp:yourmasterserver

    don't forget to:

    postmap /etc/postfix/transport

    and restart postfix

    • 0

  3. The setup is:

    $ grep domain.com /etc/postfix/*
/etc/postfix/main.cf:relay_domains = domain.com
/etc/postfix/relay_recipients:"@domain.com OK"
Binary file /etc/postfix/relay_recipients.db matches
/etc/postfix/transport:domain.com  smtp:[ip.address.of.the.mail.server]
Binary file /etc/postfix/transport.db matches

    Also don't forget:

    $ postmap /etc/postfix/transport
$ postmap  /etc/postfix/relay_recipients
$ /etc/init.d/postfix restart

    (CentOS,RedHat)

    • 0