Re: [Exim] fallback on DNS defer?

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Author: Dean Brooks
Date:  
To: John Dalbec
CC: exim-users
Subject: Re: [Exim] fallback on DNS defer?
On Fri, Apr 09, 2004 at 03:02:15PM -0400, John Dalbec wrote:

> I changed my Exim configuration so that the dnslookup router uses a
> different transport with fallback_hosts specified. This works fine
> when the remote host doesn't respond. Is there any way to get Exim to
> fall back when the DNS lookup gives a deferral?


This is the config we use for exactly that issue:

#
# Remote deliveries are attempted here. Transport failures cause
# the fallback host to be used. In the event of DNS lookup timeout,
# the pass_on_timeout entry forces our next router to be used which
# passes everything on to our fallback. Domains that get a successful
# lookup, but dont exist (NXDOMAIN), cause an immediate bounce since
# the no_more option is set.

   remote_domains:
     driver = dnslookup
     self = fail
     pass_on_timeout
     transport = remote_smtp
     fallback_hosts = fallbackhost.yourdomain.com
     no_more


#
# Fallback queue. This router is only executed when we've passed on
# DNS timeouts in our remote_domains router. The SMTP fallback_hosts
# setting does not catch DNS timeouts since fallback_hosts is actually
# handled at the transport level, not the routing level.

   send_to_fallback:
     driver = manualroute
     route_data = fallbackhost.yourdomain.com
     transport = remote_smtp


--
Dean Brooks
dean@???