Detecting a non-existent domain

Tue Sep 23 23:52:43 UTC 2003

Lee Hinckley wrote:

> At 2:46 PM -0700 9/23/03, David Schwartz wrote:

> >	He asked for the "optimal way" "to see if a given host truly
> >exists" and
> >you told him how to confirm or deny the "existance of a domain". He asked
> >about hosts, you answered about domains.

> In fairness I was ambiguous.  Although Verisign ought to be
> describing all of these techniques.  But depending on the
> circumstances I primarily need to check for A records or MX and A
> records.

	I was both confused and confusing myself. Previously, you could consider
any response other than 'NXDOMAIN' to an 'ANY' query in the COM/NET domain
to mean that the domain was registered, at least. Now you can't.

	There was no way to use DNS to tell for sure that a domain is available.
There still isn't. There was no way to use DNS to tell for sure that a
domain is registered. There still isn't.

	If we're going to challenge Verisign, we have to make sure we ask the right
questions. One question to ask them is how are we supposed to tell whether
an A record was placed by the owner of the domain. If we don't agree to
SiteFinder's terms, how do we avoid using it? How do we use DNS for
commercial purposes? And so on.

	DS