Yesterday, July 16th 2007, dnswl.org passed the mark of 5’000 users. And as of mid last week, we list more than 10’000 individual IP addresses and networks as “good” mailservers.
You can see the number of networks and hosts querying dnswl.org here (and at the very bottom of that page, you will find a link to the metadata statistics)
You may ask: “How do you measure the number of users, since DNS traffic is, by it’s very nature, highly distributed and cached?”
From all the IP addresses we see over a 24 hour period, we count all the /24 networks. An example: We may see 10.1.2.3, 10.1.2.4 and 192.168.17.23. This would be counted as two “users”, since 10.1.2.3 and 10.1.2.4 are in the same /24 (10.1.2.0/24).
This is not an exact count – but an exact count is not really possible, since there may be more than one mailserver using dnswl.org data behind a single DNS server, and a single mailserver may use more than one DNS server. We therefore assume that counting the unique /24s is a good approximation to the number of users.
The count of 5’000 does not include those users that use an rsync transfer (66 mailsystems) or download the data via HTTP (maybe a dozen currently).
One “user” is one mailsystem, and of course we have no way to determine how many individual mailboxes such a mailsystem handles (it is not even possible to reliably determine the number of mails one mailsystem receives). The size of mailsystems varies from small, personal mailservers to mailservers of big financial institutions, some larger cities, government and educational institutions.
Two weeks ago I wrote that dnswl.org has more than 5’000 users. Well, that’s a thing of the past. As of today, August 4th 2007, there are more than 12’000 users of dnswl.org (see the original article on the caveats with such numbers).
Tracked: Aug 04, 11:06