SRV (Server) RECORD INFORMATION
This type of record supports particular types of services and allows control over prioritization of delivery and usage. They specify information regarding available services for a domain. Typically used in conjunction with, but not limited to, protocols such as SIP, HTTP and LDAP.
SRV records are in the format of Host → Priority → Weight → Port → Target. (See example below).
From the above example the host has been filled in to show the service, protocol being used and domain name. The priority again is relative to other SRV records. (Similar usage to the priority in the MX record) The port and lastly the target.
Host
Host service name must start with an _ and then the protocol, for example _tcp or _udp and finally the host name. Each item is separated by a period. (_service._protocol.host)
Priority
Priority – Relative priority to other SRV records, 0 being the highest. Values must be between 0 and 65535.
Weight
Weight is used when more than one service with same priority. Higher weight takes priority. The number 0 signifies that no weighting should be used.
Port
The port is normally the number that is assigned to the associated service for the SRV record. For example, port 5060 is associated with SIP. However it is permissible for you to add a custom port. For example _http on port 8080 rather than 80.
Target
Target a domain name. Alpha-numeric characters with hyphens are allowed. Periods are also allowed between strings, not at the start or end. Can be just a hostname or full qualified domain name (FQDN). This is the host that will provide the service.