This is a discussion on Re: draft-iab-dns-choices-02.txt comments: host names vs domain names - DNS ; At Thu, 09 Jun 2005 08:03:03 -0500, 'wayne' wrote: > > So, in order to help this educational process, can someone give a > short paragraph that explains the differences between host names and > domain names, why the allowed ...
At Thu, 09 Jun 2005 08:03:03 -0500, 'wayne' wrote:
> So, in order to help this educational process, can someone give a
> short paragraph that explains the differences between host names and
> domain names, why the allowed characterset is different between the
> two and when you should use one or the other?
Really short answer: see RFC 1034 3.5 and RFC 1035 2.3.1.
Slightly longer answer: Hostnames are a proper subset of DNS names.
Hostnames have to fit the syntax defined in RFC 952 as amended by RFC
1123; DNS names only have to fit the much looser syntax defined in RFC
1035. You have to use hostnames when you're dealing with applications
that say they're dealing with hostnames or which have their own syntax
definitions which work out to be equivilent to the hostname syntax.
Since most registries will not accept DNS names that don't comply with
the hostname syntax, as a practical matter use of DNS names which are
not hostnames is for the most part restricted to applications like the
_prefix hack. Note that IDN deliberately encodes to DNS names which
do fit the hostname syntax.
As to "why?"...see the archives of the IDN WG for more details than
you ever wanted, but I won't attempt to summarize because the
opinion/fact ratio in this space is way too high.
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