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From: craig@bbn.com (Craig Partridge)
Newsgroups: comp.protocols.tcp-ip
Subject: Counting Internet Hosts (and Users)
Message-ID: <46672@bbn.COM>
Date: 9 Oct 89 17:44:00 GMT
Sender: news@bbn.COM
Reply-To: craig@BBN.COM (Craig Partridge)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 17

I can no longer find the original message, but someone last week asked
how the number of Internet hosts is counted.

The answer is that the NIC periodically runs a program that dumps the
entire domain name system (takes something like 3 days to do it) and
the Internet host count comes from counting the number of hosts in
that dump.  Note this is not a complete listing; some well-known and
large sites refuse to allow transfers of their domain data.  So when
the NIC program locates 118,000 hosts (as it did in July) you can be
sure that is an underestimate.  The guess in July was that the real
count was something over 150,000.

By the way, there is a plan afoot to actually try to estimate the number
of Internet users, by estimating the number of users per host.  The IETF
hopes to have that number by the end of this year...

Craig