Just what *is* a hostname (rfc952/1123, etc)

[Barry Margolin]

In article <a2lpnn$g67 at pub3.rc.vix.com>,
David Carmean  <dlc-bu at halibut.com> wrote:
>OK, where exactly do "hostnames" appear in the IN DNS, as opposed 
>to "domain names"?

Any place where a name is being used specifically to identify a device on
the network, as opposed to something more abstract (e.g. a service in an
SRV record).  Also, since the mail protocols specify that the thing after
the '@' in an address is a hostname, and this is processed by looking for
MX or A records, names with those types of records are hostnames.

>Cricket says: "..in the name fields of A...and MX...records....  also 
>in the data fields of SOA and NS records."
>
>So far I haven't been able to figure out from the RFCs whether a 
>hostname is just the leftmost label in a domain name, or whether 
>the *entire* domain name (fully-qualified or relative) must be 
>considered subject to the RFC952/1123 restrictions?

What difference does it make?  IIRC, the rules about hostnames apply to
each label, not the fully-qualified name.

>And what happens when I18N/L10N (whichever) rears its head?

That's a battle that's still being fought in the standards arena, I think.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.