Dynablock is a name which was used by Easynet from 2001 to 2003 for their Dialup Users List

Dialup Users List

A Dynamic Users List is a type of DNSBL which contains the IP addresses an ISP assigns to its customer on a temporary basis, often using DHCP or similar protocols. Dynamically assigned IP addresses are contrasted with static IP addresses which do not change once they have been allocated by the...

 DNSBL

DNSBL

A DNSBL is a list of IP addresses published through the Internet Domain Name Service either as a zone file that can be used by DNS server software, or as a live DNS zone that can be queried in real-time...

 of Internet addresses that appeared to be assigned dynamically, i.e. to dialup and residential broadband users.

Updates of Dynablock stopped December 2003 but it became the basis for NJABL and SORBS

Sorbs

Sorbs are a Western Slavic people of Central Europe living predominantly in Lusatia, a region on the territory of Germany and Poland. In Germany they live in the states of Brandenburg and Saxony. They speak the Sorbian languages - closely related to Polish and Czech - officially recognized and...

 own dynamic IP lists. The dynamic list parts of NJABL and SORBS have been developed independently since then, with NJABL using the 'dynablock' name for their list. In early 2007, NJABL passed their data along to The Spamhaus Project

The Spamhaus Project

The Spamhaus Project is an international organisation to track e-mail spammers and spam-related activity. It is named for the anti-spam jargon term coined by Linford, spamhaus, a pseudo-German expression for an ISP or other firm which spams or willingly provides service to spammers.-Spamhaus...

http://www.njabl.org/dynablock.html, for using in their PBL http://www.spamhaus.org/pbl service.