Re: [Exim] IPv4 only smarthost

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Author: Philip Hazel
Date:  
To: Colm MacCarthaigh
CC: exim-users
Subject: Re: [Exim] IPv4 only smarthost
On Fri, 19 Dec 2003, Colm MacCarthaigh wrote:

> I'd like to detect whether a host I'm sending mail to has an IPv4
> or IPv6 MX record. If it's Ipv4, I need to send it to a local
> smarthost (this is obviously easy enough), but if it's IPv6 I
> want to deliver it myself directly.
>
> In case I don't need to write a patch for this, is there any way
> I do this using existing configuration commands?
>
> I'm using exim 4.30 :)


Hosts don't have MX records; domains do. Any given domain might have
both IPv4 and IPv6 hosts associated with it. What you can easily do,
however, is to drop all the IPv4 hosts; if there are no addresses left,
the dnslookup router should decline. Then you can have a second router
that does the smarthost thing. Use

ignore_target_hosts = 0.0.0.0/0

on the first router. I think this will work, but I haven't tried it.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book