Detecting a non-existent domain

Wed Sep 24 00:16:04 UTC 2003

At 3:15 PM -0700 9/23/03, David Schwartz wrote:
>	How would you do this before? Does an A record for a hostname 
>mean that a
>host with that name exists? If so, then all *.com 'hosts' now 'exist'. If
>not, what did you mean by exist before?

Okay, let's be very specific.  I need to know if a given name has 
either A or MX records which are *not* the same as those provided by 
the a wildcard in the appropriate TLD.

The answer so far seems to be to query *.TLD, nab all the records, 
and then compare them all the results you get back from querying the 
domain.  If there is anything that doesn't match, you are in the 
clear.  (Modulo internal networks and localhost and all those fun 
tricks of course--but that's a different problem.)

The fact that this is a single IP comparison with Verisign today 
presumably does not preclude the wonders of MX records, CNAME's, 
multiple A records and all of that in the future.
-- 
Kee Hinckley
http://www.messagefire.com/         Next Generation Spam Defense
http://commons.somewhere.com/buzz/  Writings on Technology and Society

I'm not sure which upsets me more: that people are so unwilling to accept
responsibility for their own actions, or that they are so eager to regulate
everyone else's.