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Date: Tue, 27 Oct 2015 09:11:35 +0100
Subject: Re: Re: Would love to see reconsideration for domain and

On Mon, Oct 26, 2015 at 08:30:21PM -0400, Rich Felker wrote:
> 1. The default domain used by glibc is not the dns root but rather the
>    domain portion of the local hostname determined by gethostname().
>    Is there any value in duplicating this? Does anyone want/need it?

This is an annoying design misfeature - annoying because it
reflects and perpetuates confusion between DNS as a global name space
(for _interfaces_) and the "nodename" (for the _host_), which came from
UUCP with a very different name semantics.

It just makes no sense, besides reflecting the many existing "well
misunderstood" setups and contributing to creation of new ones.

If you ask me, don't ever rely on a certain choice of the nodename to be
the same as some record in DNS or resemble it. Too bad, a lot of programs
have been written with assumptions "a single network interface [with a
single DNS name?] and the host administrator certainly having reused
the nodename to be set to one of the dns names of the single interface;
let's report anything else as a misconfiguration".

The purpose of DNS was hardly understood when it was conceived, dealing
with "hosts" while actually it concerns "services" (the port part of the
adressing was thus left out of DNS until many years later, having been added
with SRV). The misunderstanding are now built in into the traditions and
among others in interpreting resolv.conf.

Using DNS names as if they'd refer to hardware / OS-instances ("hosts") is
in fact a misunderstanding, internet is about interfaces, not hosts,
but a way too many people fall for it.

IOW, please skip this reliance on gethostname() whenever possible at all.


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