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 a site. By setting up a few SRV records, you’ll be able to use the domain name with different companies and forward it to several servers at once, each and every server handling a different service. You can specify the port number for the connection to every single machine, so there won't be any interference. You can also set individual priorities and weight for 2 records which are used for the exact same service, but point to different servers for redundancy or load balancing. With an SRV record you can employ your domain address or a subdomain under it for a Voice-Over-IP server, for instance, and have the real software running on a number of machines with different providers. Which one a customer of yours is going to use depends on the priority and weight values that you have set.