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

On 2009-12-30 11:54:57 -0800, Russ Allbery wrote:
> Vincent Lefevre <vincent@vinc17.org> writes:
> > "stanford.edu" is definitely wrong. First it's just a domain name, not a
> > FQDN (as required by the mailname(5) man page).
> stanford.edu is an RFC 1035 FQDN.

RFC 1035 (from /usr/share/doc/RFC/links/rfc1035.txt.gz) doesn't define
what a FQDN is. It doesn't contain "FQDN", and the only occurrence of
"fully" and "qualified" is in "Gateways will also have host level
pointers at their fully qualified addresses.

FYI, here's what Wikipedia[*] (though not authoritative and sometimes
containing errors) says:

  For example, given a device with a local hostname myhost and a
  parent domain name example.com, the fully qualified domain name is
  written as myhost.example.com. This fully qualified domain name
  therefore uniquely identifies the host — while there may be many
  resources in the world called myhost, there is only one

[*] http://en.wikipedia.org/wiki/Fully_qualified_domain_name

> > This would meen that two different machines could generate the same
> > Message-Id; the right part of "@" in a Message-Id should contain the
> > hostname to avoid this kind of problems.
> The term "message ID" appears nowhere in the description of /etc/mailname.
> Why do you think it's supposed to be used for generating message IDs?

Earlier in the discussion:

  "Anything mail related must use /etc/mailname if it needs something
  that can be translated to an IP address."

> It is specifically intended for generating e-mail addresses.

In such a case, "hostname -f" (or equivalent) is still useful to
generate message-ids. And the Debian mailname(5) man page doesn't
say e-mail addresses specifically.

> > Moreover, concerning the e-mail addresses, root is local to the machine,
> > so that generating a mail from root@stanford.edu is incorrect.
> You do not know either that root is local to my system or that
> root@stanford.edu is incorrect for it.  Both of those are configuration
> *choices*, not requirements.

But root@stanford.edu wouldn't be the same root. Perhaps the Debian
mailname(5) man page should make clear what is intended for local
users and use consistent terminology.

Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)

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