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

Question

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.

Answer 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 localpart@other-domain.example 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.

Answer 2

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 user1@example.com will now be forwarded to user1@yoursite.com, etc.

I found this in this howtoforge tutorial

Answer 3

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:

/^user@olddomain.com/ user@newdomain.com

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.