postfix-users February 2011 archive
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postfix-users: Re: Conditional use of smtp_fallback_relay?

Re: Conditional use of smtp_fallback_relay?

From: Victor Duchovni <Victor.Duchovni_at_nospam>
Date: Mon Feb 07 2011 - 20:36:39 GMT
To: postfix-users@postfix.org

On Mon, Feb 07, 2011 at 08:31:03PM +0100, tobi wrote:

> Is it somehow possible to tell postfix in which error cases the
> smtp_fallback_relay should be used?

The fallback relay is used precisely when delivery tempfails.

> I'm trying to find a way to seperate
> real rejects from temporary errors.

With "real rejects" the message is bounced, and not retried.

> I want "my" postfix to use the fallback only if a reject occured

A real reject MUST cause the message to bounce, and not be retried.

> and not if a temporary error (like from greylisting) happend.

Only temporary errors are retried, this includes greylisting.

> In the later case the mails should go to the queue
> and no fallback should be used.

No. You'd have to write code to rename sufficiently old messages from
the deferred queue of the primary instance into the deferred a different
Postfix instance on the same file-system. The second instance would have
a fallback-relay setting, while the primary would not. Postfix does not
have a mechanism to apply smtp_fallback_relay to messages based on age,
nor does the queue file keep a count of the number of times a particular
message has entered the active queue (or even more complex, delivery
to a particular recipient has been attempted).

-- Viktor.