DNS Response Policy Zones - Specification - Format 3
(The link above may point to older versions of the standard; if/when this standard is adopted as an RFC by the IETF, then please follow links to that new document.)
For current information on the BIND implementation of DNS-RPZ, please refer to the Administrator Reference Manual (ARM) for the version that you are running: An Overview of BIND 9 Documentation
This memo describes a method for expressing DNS response policy inside a specially constructed DNS zone, and for processing the contents of such zones inside recursive name servers. These response policies are intended for use in fighting Internet crime and abuse. Almost all Internet crime relies on DNS, and many new and existing domains at the time of this writing are malicious.