unqualified domains, was ICANN to allow commercial gTLDs

Jeremy jbaino at gmail.com
Mon Jun 20 00:30:58 UTC 2011

"DK" may not be hierarchical, but "DK." is. If you try to resolve "DK" on
it's own, many (most? all?) DNS clients will attach the search string/domain
name of the local system in order to make it a FQDN. The same happens when
you try and resolve a non-existent domain. Such as
alskdiufwfeiuwdr3948dx.com, in wireshark I see the initial request followed
by  alskdiufwfeiuwdr3948dx.com.gateway.2wire.net. However if I qualify it
with the trailing dot, it stops after the first lookup. DK. is a valid FQDN
and should be considered hierarchical due to the dot being the root and
anything before that is a branch off of the root. see RFC1034


On Sun, Jun 19, 2011 at 7:08 PM, Mark Andrews <marka at isc.org> wrote:

> In message <g339j59ywz.fsf at nsa.vix.com>, Paul Vixie writes:
> > Adam Atkinson <ghira at mistral.co.uk> writes:
> >
> > > It was a very long time ago, but I seem to recall being shown
> http://dk,
> > > the home page of Denmark, some time in the mid 90s.
> > >
> > > Must I be recalling incorrectly?
> >
> > no you need not must be.  it would work as long as no dk.this or dk.that
> > would be found first in a search list containing 'this' and 'that', where
> > the default search list is normally the parent domain name of your own
> > hostname (so for me on six.vix.com the search list would be vix.com and
> > so as long as dk.vix.com did not exist then http://dk/ would reach
> "dk.")
> > --
> > Paul Vixie
> > KI6YSY
> DK should NOT be doing this.  DK is *not* a hierarchical host name
> and the address record should not exist, RFC 897.  The Internet
> stopped using simple host names in the early '80s.  In addition to
> that it is a security issue similar to that described in RFC 1535.
> Mark
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org

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