Re: DNS vs /etc/hosts

From: Michael Fuhr <mike(at)fuhr(dot)org>
To: Lowell(dot)Hought(at)faa(dot)gov
Cc: pgsql-general(at)postgresql(dot)org, Richard_D_Levine(at)raytheon(dot)com
Subject: Re: DNS vs /etc/hosts
Date: 2005-08-04 22:49:22
Message-ID: 20050804224922.GA90868@winnie.fuhr.org
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On Thu, Aug 04, 2005 at 04:39:02PM -0500, Lowell(dot)Hought(at)faa(dot)gov wrote:
> The difference must have to do with the functions that differ in the
> different versions of psql. In looking through the code for version 8.0
> in the file /interfaces/libpq/ip.c, the function that resolves hostname is
> "getaddrinfo". Is this the same function that was used in version 7.2,
> and if not, how does it differ? Is there something on my machine that I
> can configure?

Good catch -- the use of getaddrinfo() appears to have been added
in 7.4. I see calls to inet_aton() and gethostbyname() in earlier
versions, so maybe that explains the difference. A simple test
program should be able to confirm or refute that hypothesis. The
tcpdump output I suggested in another message should show exactly
what queries are being made and what responses are being received.

Different systems have different resolver customizations; you'll
have to check your local documentation. I'd start with "man
resolv.conf". I'd especially look for options that control if and
when queries for the top-level domain "hostname" are made when
queries for "hostname.domain" fail. You might also want to examine
your domain search list.

--
Michael Fuhr

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