SRV, which is an abbreviation for Service, is a DNS record, which allows you to use a domain name for a specific service different from an Internet site. By setting up a number of SRV records, you can use the domain with different companies and point it to a number of servers at once, each server handling a different service. You are able to specify the port number for the connection to every single machine, so there will never be any interference. You could also set different priorities and weight for 2 records which are employed for the same service, but point 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 several machines with different companies. Which one a customer of yours is going to use will depend on the priority and weight values that you have set.