Dynamic Delegation Discovery System
（重定向自DDDS）
Defined in RFC 3401, RFC 3402, RFC 3403, RFC 3404, and RFC 3405. The primary container used to hold DDDS information is the NAPTR record.
From RFC 3401:
DDDS defines a mechanism for using DNS as the database for arbitrary identifier schemes.
ENUM (RFC 6116) is defined as a DDDS application to resolve phone numbers into data stored in DNS.