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 a website. By setting up a few SRV records, you’ll be able to use the domain with different companies and point it to several servers at a time, every single server handling a separate service. You are able to specify the port number for the connection to each machine, so there will not be any interference. You could also set individual priorities and weight for two records that are employed for the exact same service, but direct to different servers for redundancy or load balancing. By having an SRV record you can use your domain name or a subdomain under it for a Voice-Over-IP server, for example, and have the specific software running on several machines with different companies. Which one a client of yours is going to use depends on the priority and weight values you have set.