Subject: The *new* Internet Domain Survey, January 19980

From: Network Wizards <[email-masked]>
Date: Fri, 6 Feb 98 2:04:47 PST

Internet Domain Survey            Network Wizards             January 1998

*** The technique we have used for the Internet Domain Survey has changed.
*** Please read this note for more info and then see our web site.

                                http://www.nw.com

The Domain Survey attempts to discover every host on the Internet by doing
a complete search of the Domain Name System.

Network Wizards has published data from its Internet Domain Survey since
1987.  However, over the last few years, the Domain Survey has not been
able to count all the hosts in the domain system due to some organizations
restricting access to their domain data.  The blocking of downloads (zone
transfers) has increased to the point where in the July 1997 survey we
could only download 75% of the domains we discovered.  We decided to try a
new survey technique.

The new survey technique uses DNS PTR queries to lookup a hostname assigned
to a particular IP address.  This is done for every possible IP address in
order to discover every host.  We do not have to query all 2^32 addresses,
just the ones that have an IN-ADDR.ARPA delegation.  In effect, the old
survey counted how many names were assigned an IP address, and the new
survey counts how many IP addresses are assigned a name.

The results are about what we expected.  However we urge people not to
compare these results directly with the previous surveys.  On our web site,
you will find the survey results, and a much longer explanation of how the
survey works and the problems and observations that go with it.  You will
also find a breakdown of hosts by top-level-domain, along with counts of
how many 2nd and 3rd level names exist under each TLD.

                                                          -- Mark Lottor