This test will list DNS SRV-Records for a domain. The DNS SRV-Record lookup is done directly against the domain's authoritative name server, so changes to DNS SRV-Records should show up instantly. DNS SRV-Records are used to provide information about available services available for a domain. The naming system is an underscore followed by the name of the service, followed by a period, and underscore, and then the protocol, another period, and then the name of the domain.