Re: [Exim] Some questions

Hi,

On Sat, Aug 10, 2002 at 08:05:20PM +0200, Chris Knipe wrote:
> That's how I understand it as well, and to my understanding how it should
> work. However, what is required on the secondary MX machine to let it know
> to queue and re-route the domains?

Let me give you an example:

You have

pop1domain.com
pop2domain.com

relay1domain.com
relay2domain.com

Furthermore you have a forward user@??? -> user@???

The pop mailboxes are on the primary mailserver and relay1domain.com and
relay2domain.com should be routed to fixed IP addresses.

You configure the primary mailserver to accept pop?domain.com and to
relay relay?domain.com to the SMTP hosts that should get the mail.
Furthermore, if mail comes for user@???, the mailserver
should pass it along.

Now you configure the second one the same, except for the pop?domain.com
domains. They are now relay domains, too, but have set the primary
mailserver as the SMTP target to relay these domains to.

If the first goes down, the second server can pass along mail for
relay?domain.com, since it knows where to send them. Furthermore it can
forward mails to user@??? if it knows where to send it
(database, ldap, files...)
Any other mail will get routed to the primary mailserver, if it
responds, fine - the mail is done for the second server. If it doesn't,
the second server queues it and tries again later.


> A domain for which the secondary MX is there, the domain cannot be specified
> in local_domains because the secondary MX will not process any deliveries
> for the domain, so what exactly is needed here?

The secondary relays the pop domains (you call them local domains,
okay) and passes them to the primary if it can be reached - and queues
it otherwise.


I hope this is clearer :-)


Joachim

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