Important update:
It's been more than 6 months since NJABL maintenance of dynablock was terminated and dynablock became a copy of the Spamhaus PBL. The dynablock zone has been emptied and the dynablock.njabl.org zone will be shut down in the near future. If you're still using dynablock.njabl.org, it's long past time to switch to pbl.spamhaus.org.

Dynablock.njabl.org started out as a straight import of what was dynablock.easynet.nl...a very nice DNSBL of dynamic IP spaces, which the maintainer got tired of maintaining and announced would be shut down December 1, 2003. From December of 2003 until January of 2007, NJABL maintained its own copy of the dynablock zone.

With the advent of Spamhaus's PBL, dynablock has become obsolete. Rather than maintain separate similar DNSBL zones, NJABL will be working with Spamhaus on the PBL. For the next several months, dynablock.njabl.org will exist as a copy of the Spamhaus PBL. After dynablock users have had ample time to update their configurations, the dynablock.njabl.org zone will be emptied.

If you currently use dynablock.njabl.org we recommend you switch immediately to pbl.spamhaus.org. If you currently use combined.njabl.org, we recommend you add pbl.spamhaus.org to the list of DNSBLs you use. You may also want to consider using zen.spamhaus.org, which is a combination zone consisting of Spamhaus's SBL, XBL, and PBL zones.

It should also be noted that there's a subtle distinction between exactly what dynablock was and the Spamhaus PBL is. The goal with dynablock was to list dynamic IP pools. The PBL includes such pools as well, but in addition, network owners may list in the PBL any of their IP addresses which are not supposed to send direct-to-mx email. This makes the PBL, and zen, as it includes the PBL, questionably suitable for anything other than filtering or scoring based on the IP address talking to your mail server.

Since we no longer directly maintain the dynablock.njabl.org zone, any additions or removals must be done via the Spamhaus web site. Do not email NJABL asking for removals.

As an ISP or other "network operator", you are encouraged to use the Spamhaus PBL web site to register which parts of your IP space should not be sending "direct to MX" email over the internet.

As an end-user running a mail server on a static IP that's been mistakenly listed in the PBL, you can use the Spamhaus PBL web site to register an exclusion for your IP, removing it from the PBL (and dynablock).

For compatibility with dnsbl.njabl.org, all dynablock.njabl.org listings return an A record of 127.0.0.3 and (other than the 127.0.0.3 test listing) all return the same TXT record, currently:
Dynamic/Residential IP range listed by NJABL dynablock - http://njabl.org/dynablock.html