SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain for a specific service different from a website. By setting up a number of SRV records, you will be able to use the domain with different companies and point it to several servers at once, each and every server handling a different service. You are able to specify the port number for the connection to every machine, so there will not be any interference. You can also set different priorities and weight for 2 records which are employed for the very same service, but direct to different servers for redundancy or load balancing. Using an SRV record you can employ your domain name or a subdomain under it for a Voice-Over-IP server, for example, and have the actual software running on a number of machines with different providers. Which one a customer of yours will use depends on the priority and weight values you have set.