SRV Record: Also known as a Service record. An SRV record is intended to provide information on available services. A SRV record has four fields and a unique system for naming. The naming system is an underscore followed by the name of the service, followed by a period, and underscore, and then the protocol, another dot, and then the name of the domain. The four fields are.
1. Priority, just a in MX records
2. Weight, used to determine relative capacity between to SRV fields with the priority. Hits will be assigned proportionately by weight, allowing a powerful and a weak server to share appropriate loads.
3. Port, the port of the service offered
_http._tcp.example.com. SRV 10 5 80. www.example.com