Dynamic Delegation Discovery System

The Dynamic Delegation Discovery System (DDDS) is an algorithm for applying string transformation rules to application-unique strings to extract specific syntax elements. It is used for finding information, such as authoritative domain name servers, for Uniform Resource Identifiers and Uniform Resource Names. An earlier specification applied only to URNs, and was called the Resolver Discovery Service (RDS).

DDDS defines a mechanism for using the Domain Name System (DNS) as the database for arbitrary identifier schemes. The primary logical DNS container used to hold DDDS information is the NAPTR record.

DDDS is defined in

RFC 3401 expresses the system as follows:

Telephone Number Mapping (ENUM), specified in RFC 6116, is defined as a DDDS application to resolve telephone numbers into DNS data.