ENUM zones provide voice over IP (VoIP) functionality within a DNS server.
The system requires DNS to manage the phone numbers associated with client end points; Address Manager provides an E164 or ENUM zone type for this purpose. The ENUM zone represents the area code for the phone prefixes and numbers stored in it. ENUM zones contain special sub-zones called prefixes that represent telephone exchanges and can contain the records for the actual devices.
VoIP devices are addressed in several ways. A uniform resource identifier (URI) string provides custom forward locator references for these devices as covered in RFC 3401. Reverse DNS is used to discover the relevant information for a device based on its phone number. Name authority pointer (NAPTR) records are used to represent this information.