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Re: where is /etc/hosts supposed to come from?

Vincent Lefevre <vincent@vinc17.org> writes:

> RFC 5322 doesn't mention "FQDN", "fully" or "qualified" either!  Perhaps
> you meant RFC 5321, which uses "FQDN" with a different meaning, and uses
> "primary host name" for what is a FQDN here.

Sorry, yes, that's the one I meant.  The mail format standard defines for
itself what, in essence, an FQDN is, but it doesn't use that terminology
and it does so only in the context of e-mail addresses.

> RFC 5321 also says "In the EHLO command, the host sending the command
> identifies itself", implying that what you give after EHLO must be
> unique (otherwise that's no longer an identification).

Uh, no.  That statement implies nothing of the sort; identification is not
necessarily unique.

> On 2009-12-31 12:37:25 -0800, Russ Allbery wrote:

>> You're right, that's not authoritative and, in this case, is
>> misleading.  Nothing about an FDQN implies uniqueness.  Wikipedia is
>> trying to get at the distinction between an unqualified name, which
>> could duplicate many other unqualified names in other domains, and a
>> fully-qualified name which has a single location in the DNS hierarchy.
>> However, an FQDN, despite living in one place in the DNS hierarchy, may
>> refer to multiple separate systems (as it does for stanford.edu,
>> time.stanford.edu, etc., all of which are FQDNs).

> No, they are not FQDNs of the corresponding hosts. For instance,
> time.stanford.edu resolves to 3 IP addresses (3 hosts, I suppose):

I've been participating in standardization of network protocols through
the IETF for more than a decade now, and I've never seen someone use this
definition of FQDN that you're using.  I'm quite confident that this is
not the intented interpretation of the standards to which you're
referring, in large part because I was participating in the mailing lists
on which they were written.

I'm going to bow out at this point, since I don't think either of us
are going to convince each other and so far as I can tell, no concrete
change is being proposed, so this is all sort of pointless.  If someone
proposes a concrete change, that's the point at which this all becomes
relevant to debate.

Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>

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