SRV

A Service Record (SRV record) is a specification of data in the Domain Name System containing information about IP and port for a specific service.

It is used by domain servers to keep track of their own changes without having to contact a central DNS server.

An SRV record has the form:

_Service._Proto.Name TTL Class SRV Priority Weight Port Target

Item	Description
Service	Identifier for the service.
Proto	The service protocol.
Name	Domain name where the record is valid.
TTL	DNS time to live.
Class	DNS class (IN for Internet).
Priority	Target host priority, lower value means more preferred.
Weight	A relative weight for records with the same priority.
Port	Port for the service.
Target	Hostname for the service provider.