Re: [exim] Fixing IPV6 network is unreachable error messages

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Author: James R Grinter
Date:  
To: exim-users
Subject: Re: [exim] Fixing IPV6 network is unreachable error messages
On 29/03/2013 19:23, Thomas Leavitt wrote:
> I've dug through Google thoroughly, and don't see any reference to this,
> nor do I see any instructions in the Exim4 documentation or on the wiki.


from the canonical documentation, doc/spec.txt, in Exim's source code:

13.6 Disabling IPv6
-------------------

Sometimes it happens that an Exim binary that was compiled with
IPv6 support is run on a host whose kernel does not support IPv6.
The binary will fall back to using IPv4, but it may waste resources
looking up AAAA records, and trying to connect to IPv6 addresses,
causing delays to mail delivery. If you set the disable_ipv6 option
true, even if the Exim binary has IPv6 support, no IPv6
activities take place. AAAA records are never looked up, and any
IPv6 addresses that are listed in local_interfaces, data for the
manualroute router, etc. are ignored. If IP literals are enabled,
the ipliteral router declines to handle IPv6 literal addresses.

also, it says that it goes in the main section, i.e. at the top before ACLs,
Rewrites, and other things beginning with 'begin'.

(I can't see any compilation options that would prevent the option existing
- and it's not a new one - but I'm not familiar with the modifications that
some Linux distributions choose to make.

It looks like yours might be generating the configuration file Exim actually
uses, from individual files - so you might want to check that you're putting
it into the correct file or creating the option in a new file with the
correct filename.)

Alternatively, configure your system to not establish IPv6 addresses on
network interfaces if you don't have IPv6 connectivity.

James.