postfix-users October 2010 archive
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postfix-users: Re: Deliver mail to multiple queues

Re: Deliver mail to multiple queues

From: Wietse Venema <wietse_at_nospam>
Date: Thu Oct 07 2010 - 20:00:10 GMT
To: Postfix users <postfix-users@postfix.org>

Joseph L. Casale:
> >Please describe the problem that you are trying to solve, instead
> >of the solution that you have come up with (queue duplication).
>
> Sorry guys, just trying to be brief. I have an unrelated issue with other
> software whereby a rollback this weekend will likely take place on the
> mailbox server (client access will be prevented all weekend).
>
> My Postfix gateway will be receiving inbound mail and unfortunately
> I don't have the option this time to change DNS entries and some of
> the maintenance will require receiving mail for this domain.
>
> Normally, whenever we do maintenance, we edit the transport file
> from "domain.com smtp:[10.0.0.5]" to "domain.com hold:[10.0.0.5]"
> which references a "defer_transports = hold" in the main.cf.
>
> I need to be able to replay any inbound mail back into our mailbox
> server if it gets rolled back (virtual server) and this will be the easiest
> way.

What is the problem? Your gateway server forwards mail to the
mailbox server as usual, but then the mailbox server is "reset" to
some earlier checkpoint, causing all mail to be lost that was
delivered since that earlier checkpoint. The mail is no longer on
your gateway server, so there is no mail to replay.

The proper solution is not to deliver that mail to the mailbox server.

For example, turn off the mail software on the mailbox server before
making the checkpoint, or do something on the gateway server that
keeps it from sending mail to the mailbox server. Besides playing
games with defer_transports, you could use a firewall rule or
something else that prevents mail from traveling to the mailbox
server.

        Wietse