Our previous method of enforcing limits caused some concern, both in public and private conversations. The main argument is that causing false negatives is not acceptable in principle, not even for cases of obvious abusive use.
We listened to these thoughts, and have now changed our approach. The criteria for blocking such abusive nameservers are still the same: repeated use way above the 100k / 24 hours limit and no response to reasonable attempts at contacting them. Also, most of the things in our previous news item referenced above are still valid.
We restrict the use of the public dnswl.org nameservers to 100’000 queries per day for all organisations using it for free. With this limitation, we want to keep the traffic for all public mirrors (some of which are donated) at an acceptable level (currently 100 to 200 GByte per month).
Sometime today, Nov 27 2010, amidst the hardware problems with one of our servers, we silently passed the milestone of 100’000 active entries in the dnswl.org database (it’s slightly more IP addresses, because there are also some ranges of IP addresses in our database). That data is used by about 50’000 organisations world-wide.
As announced earlier, dnswl.org is changing it’s operating model. Users with high query volumes (> 100’000 queries/24 hours) and commercial filter vendors of anti-spam products and services are required to purchase a subscription (see here for full access requirements).