This type of DNS record allows a user to locate a specific service on a network rather than a specific machine. An A Record is designed to locate a server or host while the SRV record locates a service provided on the network. The service could be a printer, VoIP, FTP, or other similar services. They work similar to how MX Records function, just with different types of services.
- Service: Symbolic name of the desired service
- TTL: Standard DNS time to live field
- Preference: The priority of the target host, lower value means more preferred. The priority can be any number between 0 and 65535
- Weight: A relative weight for Records with the same priority. Determines which of the Records with the same priority are delivered more frequently. Enter the proportional volume of traffic as a percent.
- Port: The TCP or UDP port on which the service is to be found.
- Server: The domain name for which this record is valid
- Host: The name of the machine providing the service.
An SRV record has the textual form:
_service._protocol.domainname TTL IN SRV priority weight port target
Below are two examples for the Extensible Messaging and Presence Protocol (XMPP). The first line represents the form and the line below it is the actual record.
_xmpp-client._tcp.example.net. TTL IN SRV priority weight port target
_xmpp-client._tcp.example.net. 86400 IN SRV 5 0 5222 example.net.
_xmpp-server._tcp.example.net. TTL IN SRV priority weight port target
_xmpp-server._tcp.example.net. 86400 IN SRV 5 0 5269 example.net.
