postfix-users October 2010 archive
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postfix-users: Re: Postfix as TLS client using different credent

Re: Postfix as TLS client using different credentials for same SMTP host

From: Wietse Venema <wietse_at_nospam>
Date: Mon Oct 11 2010 - 19:13:42 GMT
To: Postfix users <postfix-users@postfix.org>

Chris Hills:
[ Charset ISO-8859-1 unsupported, converting... ]
> Hi
>
> The situation is thus:-
>
> I wish to provide a v6-to-v4 relay for two different domains using the
> same postfix process. Mail for the domains is hosted by google, so the
> destination host will be ASPMX.L.GOOGLE.com. for both domains. However,
> recently my ipv4 provider has blocked outgoing tcp:25 so now I must use
> tcp:587 using TLS and authentication. The problem is that I need to use
> two different credentials depending upon the domain for which the
> message is being relayed.
>
> i.e.
>
> user@domain1.example.com -> postfix -> ASPMX.L.GOOGLE.com. (user: domain1)
> user@domain2.example.com -> postfix -> ASPMX.L.GOOGLE.com. (user: domain2)
>
> How do I configure this?

Two solutions:

1) Use separate Postfix MTA instances for each domains. See:
   http://www.postfix.org/MULTI_INSTANCE_README.html

2) Use one Postfix MTA instance with sender-dependent personalities. See:

   http://www.postfix.org/postconf.5.html#sender_dependent_default_transport_maps

   and configure mail delivery transports

        smtp-for-domain1 . . . . . . . smtp
            -o smtp_tls_foo=xxx....
        smtp-for-domain2 . . . . . . . smtp
            -o smtp_tls_foo=yyy....

   overrides in master.cf.

   See: http://www.postfix.org/master.5.html for master file syntax.

        Wietse