What is SRV record? How to add SRV entry in DNS zone file?
A Service record (SRV record) is a specification of data in the Domain Name System defining the location, i.e. the host name and port number, of servers for specified services.
An SRV record has the form:
_service._proto.name TTL class SRV priority weight port target
service: the symbolic name of the desired service.
proto: the transport protocol of the desired service; this is usually either TCP or UDP.
name: the domain name for which this record is valid.
TTL: standard DNS time to live field.
class: standard DNS class field (this is always IN).
priority: the priority of the target host, lower value means more preferred.
weight: A relative weight for records with the same priority.
port: the TCP or UDP port on which the service is to be found.
target: the canonical host name of the machine providing the service.
_sip._tcp.example.com. 14400 IN SRV 0 5 443 sipserver.example.com.
Retrieving an SRV record:
$ dig SRV _sip._tcp.example.com
$ host -t SRV _sip._tcp.example.com
$ nslookup -type=srv _sip._tcp.example.com
> set type=srv