Re: [exim] Use DNS then fall back to local delivery

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Author: Dominic Hargreaves
Date:  
To: exim-users
Subject: Re: [exim] Use DNS then fall back to local delivery
On Sat, Oct 03, 2009 at 05:57:09PM -0700, Gregg Lain wrote:
> I am setting up 2 VPS's for redundancy - I am trying to work this out:
>
> Primary - exim, its the first MX preference
> Secondary exim, second Mx preference + same local accounts as on Primary
>
> Looking to setup the following router that would be global
>
> mail arrives either locally or comes in that matches local user, then
> looks at DNS first to see where to deliver, sees that primary is on
> other server and off it goes.
> if the primary server was down, the second MX record points to this
> server, then the delivery is made there.
>
> I don't want to relay, but actually have it delivered - so that its
> readable during the primary server outage.


I've not used it, but if you define a router on the secondary host
that does remote delivery to the primary with pass_on_timeout set,
and then after that another router that does the local delivery, does
that help?

It only mentions DNS timeouts as opposed to connect timeouts, so I'm
not sure if it will do exactly what you want, but it's worth a try.

http://www.exim.org/exim-html-current/doc/html/spec_html/ch15.html

The other way would be to invent a generic condition (could execute
some external command) to test whether the primary host is up, and
list that in the first router with 'condition'.

Cheers,
Dominic

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Dominic Hargreaves | http://www.larted.org.uk/~dom/
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