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Abraham Vegh
Asked: 2011-09-20 07:47:55 +0800 CST

Use Postfix to forward mail to a domain to the same address at a different domain

  • 772

Is there a way to configure Postfix to accept any mail for a domain (catch-all), and then forward that email to the same recipient at a different domain, ignorant of whether the recipient actually exists?

I use Postfix with a MySQL backing for virtual accounts.

postfix

5 Answers

  1. No this is not directly possible. There is one exception how it can work described in http://www.postfix.org/ADDRESS_REWRITING_README.html#luser_relay

    Another crude solution would be to use SQL (substr + concat) to handle this for you in the virtual_alias_maps.

    Edit: Oh. There is one last possibility. Use the policy delegation mechanism and return REDIRECT [email protected] where you need it and DUNNO if you don't want to rewrite.

    Edit 2: Inspired by Squidly (but his solution does not work!) you can setup

    virtual_alias_maps = pcre:/etc/postfix/forward_user.pcre, ...

    and in that file put

    /^(.*)@adomain\.example/    $(1)@other-domain.example

    (Watch out for the escaped dot (\.) in the first column.) Personally I would prefer this version.

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  2. The pcre table type is unavailable on my system, so I did the following:

    • In /etc/postfix/main.cf:

      virtual_alias_maps = regexp:/etc/postfix/virtual

    • In /etc/postfix/virtual:

      /^([^@]*)@olddomain/ $(1)@newdomain
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  3. Not directly possible? I found it very simple and direct with no SQL, regular expressions, or policy mechanisms.

    In main.cf:

    virtual_alias_domains = alias-destination1.com alias-destination2.com
virtual_alias_maps = hash:/etc/postfix/virtual

    In /etc/postfix/virtual:

    # I want @true-destination.com to have two incoming aliases
@alias-destination1.com @true-destination.com
@alias-destination2.com @true-destination.com

    Sending a test e-mail from the server:

    # telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 smtp.myserver.com ESMTP Postfix
HELO smtp.myserver.com
250 smtp.myserver.com
MAIL FROM:<[email protected]>
RCPT TO:<[email protected]>
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Message-ID: <[email protected]>                                                                                                               
Date: Thu, 05 May 2011 23:59:59 -0400                                                                                                                    
From: Some Body <[email protected]>                                                                                                                   
To: [email protected]                                                                                                                                
Subject: Hello                                                                                                                                           
Just testing.                                                                                                                                            
.

    And the actual result in mail.log (I have amavis on port 10025 running):

    Apr  6 22:39:43 smtp-a postfix/smtpd[4411]: connect from localhost[127.0.0.1]
Apr  6 22:39:43 smtp-a postfix/smtpd[4411]: 6B47641AF2: client=localhost[127.0.0.1]
Apr  6 22:39:43 smtp-a postfix/cleanup[3706]: 6B47641AF2: message-id=<[email protected]>
Apr  6 22:39:43 smtp-a postfix/qmgr[3681]: 6B47641AF2: from=<[email protected]>, size=1115, nrcpt=1 (queue active)
Apr  6 22:39:43 smtp-a postfix/smtpd[4411]: disconnect from localhost[127.0.0.1]
Apr  6 22:39:43 smtp-a amavis-incoming[2159]: (02159-13) Passed CLEAN {RelayedInternal}, LOCAL [127.0.0.1]:42426 [127.0.0.1] <[email protected]> -> <[email protected]>, Queue-ID: 5C61F41AE5, Message-ID: <[email protected]>, mail_id: hUbzH1PtXlzl, Hits: 2.605, size: 394, queued_as: 6B47641AF2, 1224 ms
Apr  6 22:39:43 smtp-a postfix/lmtp[3687]: 5C61F41AE5: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=25, delays=24/0/0/1.2, dsn=2.0.0, status=sent (250 2.0.0 from MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as 6B47641AF2)
Apr  6 22:39:43 smtp-a postfix/qmgr[3681]: 5C61F41AE5: removed

    Key line separated for emphasis:

    Apr  6 22:39:43 smtp-a postfix/smtp[3684]: 6B47641AF2: to=<[email protected]>, orig_to=<[email protected]>, relay=10.0.0.245[10.0.0.245]:2525, delay=0.03, delays=0.01/0/0/0.02, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 705AA40459)
Apr  6 22:39:43 smtp-a postfix/qmgr[3681]: 6B47641AF2: removed
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  4. If you use MySQL as the storage end, I believe that you can specify a catch all forward like this:

    Table Forwardings

    | source       | destination   |
|==============|===============|
| @example.com | @yoursite.com |

    If I read the documentation right, it would mean that [email protected] will now be forwarded to [email protected], etc.

    I found this in this howtoforge tutorial

    • 0

  5. Depending on how you setup your Postfix you may be able to use an alias to forward all mail.

    edit

    Also you can setup a redirect that will do it for you easily.

    In /etc/postfix/main.cf add this:

    recipient_bcc_maps = pcre:/etc/postfix/forward_bcc.pcre

    Then in /etc/postfix/forward_bcc.pcre add this:

    /^[email protected]/ [email protected]

    This is a bit of a hack but it will work for forwarding specific users from one domain to another.

    You also may want to look at this page for how to do some rewriting within Postfix it's self.

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