RE: [Exim] @mx_any/ignore & route_list interpretation

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Author: Eli
Date:  
To: exim-users
Subject: RE: [Exim] @mx_any/ignore & route_list interpretation
Philip Hazel wrote:
> On Wed, 23 Jun 2004, Eli wrote:
>
>> My 2nd question is with regards to route_item and how it's items are
>> expanded. I read the documentation and for the most part it
>> mentions that route_list is to be a list of DOMAIN NAMES that get
>> resolved to get the IP addresses. However, a few places mention
>> that it can also be an IP address (which is what I'd prefer to use).
>
>> From the manual:
>
> 20.4 Format of the list of hosts
>
> A list of hosts, whether obtained via "route_data" or "route_list",
> is always separately expanded before use. If the expansion fails,
> the router declines. The result of the expansion must be a
> colon-separated list of names and/or IP addresses. IP addresses are
> not enclosed in brackets.


Yeah that's what I had read as well (obviously), but I'm still wondering why
running Exim in -d debug mode appears to show Exim trying to do a DNS lookup
on the IP addresses - is it because it just passes everything in the list to
a resolver? Does the resolver portion know an IP from a hostname and
doesn't really do a DNS lookup and just returns the IP immediately? If so
then I'm all happy. I guess I'm just concerned about Exim looking like it's
trying to resolve an IP and wasting some time doing so.

The only reference I found to having Exim not resolve the entries in the
list was:

    When an address is routed to a local transport, IP addresses are
    not looked up. The host list is passed to the transport in the
    $host variable.


Eli.