From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark H Weaver <mhw@netris.org>
Subject: Re: Neon and reverse address lookup
Date: Sat, 18 Jan 2014 16:55:50 -0500
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References: <20140118124847.GA6166@debian> <8738klou1c.fsf@gnu.org>
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In-Reply-To: <8738klou1c.fsf@gnu.org> ("Ludovic
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To: Ludovic =?utf-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Cc: guix-devel@gnu.org

ludo@gnu.org (Ludovic Court=C3=A8s) writes:

> So /etc/hosts is not enough for reverse lookups to work.
>
> With nscd turned off, I tried this:
>
>   guile -c '(pk (gethostbyaddr (inet-pton AF_INET "127.0.0.1")))'
>
> If nsswitch.conf is removed, then that resolves to =E2=80=9Clocalhost=E2=
=80=9D (instead
> of the actual host name.)

As John said, it should resolve to "localhost".  It certainly should
_not_ resolve to the actual host name.

> If, in addition, resolv.conf is removed, then that fails as seen above.
>
> With nsswitch.conf alone, it resolves correctly (Mark was right.)
> And this works with only =E2=80=9Chosts: files=E2=80=9D in nsswitch.conf.

When you say "it resolves correctly", which name does it resolve to?

> It=E2=80=99s surprising that there=E2=80=99s this discrepancy between how=
 NSS works for
> getaddrinfo and for gethostbyaddr.  At any rate, we may be able to solve
> this at the libc level.

Solve what?  What are you thinking of changing in libc?

     Mark