SRV, which is an abbreviation for Service, is a DNS record, which enables you to use a domain name for a specific service different from an Internet site. By setting up a number of SRV records, you’ll be able to use the domain with different companies and point it to several servers at a time, each and every server handling a separate service. You'll be able to specify the port number for the connection to each and every machine, so there will not be any interference. You may as well set individual priorities and weight for 2 records which are used for the very same service, but forward to different servers for redundancy or load balancing. By having an SRV record you can use your domain address or a subdomain under it for a Voice-Over-IP server, for example, and have the actual software running on several machines with different companies. Which one a customer of yours will use will depend on the priority and weight values that you've set.