SRV, which is an abbreviation for Service, is a DNS record, which permits you to use a domain name for a specific service different from a website. By creating a number of SRV records, you will be able to use the domain name with different companies and forward it to numerous servers at a time, each and every server managing a separate service. You can specify the port number for the connection to each and every machine, so there will never be any interference. You may as well set different priorities and weight for 2 records that are used for the very same service, but direct to different servers for redundancy or load balancing. With 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 various machines with different providers. Which one a customer of yours will use will depend on the priority and weight values which you have set.