The ‘service’ record specifies a host and port for specific services such as Voice Over IP (VOIP), instant messaging, etc. When an application needs to find the location of a specific service, it will search for a related SRV record. If it finds one, it will sift through the list of services and their connecting hostnames to find the following:

• Hostname
• Ports
• Priority and Weight 
• IP Addresses, if relevant

Example of an SRV record:

In the above example, ‘_sip’ indicates the type of service, ‘_tcp’ indicates the protocol, and ‘8080’ indicates the port while ‘example.com’ is the host.