A Service (SRV) Resource Record can be created on a Domain Name Server (DNS) for making IP-based services easier to find in a domain. Additional information about a service may be made available (such as the server running the service, priority and so forth).
Such a Service Resource Record can be created as follows:
_sipfederationtls Service Location (SRV)  ucserver.domain.de.
|_sipfederationtls||The name of the services which are found in the DNS. For the federation, the name must be _sipfederationtls.|
|Service Location (SRV)||The type of record contained by these lines.|
|||The priority of the service so that different, similar records can be prioritized. Not in use.|
|||Emphasizes the entry. It is not used|
|||Here the port number is provided from which the service provides the service. For the federation the default is generally valid: standard SIP on port 5061.|
|ucserver.domain.com||The computer which offers the service. Here, the federation expects the computer on which the UCServer runs.|
How and where the Service Resource Records are created for specific DNS servers can be found in the corresponding manufacturer's documentation.