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Accepted
ThatGraemeGuy
Asked: 2011-06-16 00:49:45 +0800 CST

How do I configure postfix to deliver mail for specified domains to another host, and deliver the rest using MX records

  • 772

We currently have postfix handling emails generated by a number of apps. A number of these emails are destined for users inside the organisation, whose mail is on an Exchange server in the same site as the postfix box.

I'm looking for a way to do this, but my Google-fu is letting me down:

If the recipient domain is one of our domains, deliver the mail to host mail.example.com. All other mail is delivered by looking up the MX record/s and processing normally.

Edit: to clarify, the apps generating the emails are sending to users outside of our organisation too, postfix is not receiving mail at all.

postfix

2 Answers

  1. Best Answer

    Instructions work for Ubuntu, you may need to adjust for other distros.

    Add the following to /etc/postfix/main.cf:

    relay_domains = domain1.com, domain2.com
transport_maps = hash:/etc/postfix/transport
relay_recipient_maps = hash:/etc/postfix/relay_recipients
relay_transport = relay

    Create the file /etc/postfix/transport:

    domain1.com  smtp:[mail.example.com]
domain2.com  smtp:[mail.example.com]

    Create the file /etc/postfix/relay_recipients:

    @domain1.com x
@domain2.com x

    Run these commands:

    $ sudo postmap /etc/postfix/transport
$ sudo postmap /etc/postfix/relay_recipients
$ sudo /etc/init.d/postfix reload
    • 14

  2. Sounds like your postifx box is acting as a secondary MX (with Exchange as the primary). Just configure it as such.

    • -1