Ever wondered what the purpose of an SRV record is? Well, SRV records are a little bit different from most DNS records because they are not directly related to the DNS server – they look after separate domain services. Let’s take a look.
An introduction to SRV records
The world of server technology is changing and the opportunities for domain owners to manage the way their domains behave has increased. Hosting providers are competing on the ability to offer enhanced, custom ways to manage DNS. Clients consider absolute control over DNS an important factor when it comes to managing domains, including the way domains behave on the internet.
Most DNS control panel options include the ability to change records that are directly connected with domain management, including A records and MX records as well as the useful CNAME records. SRV records are set apart, and are mainly to do with managing separate domain services.
Explaining SRV records
The “S” in SRV records stands for service, and so SRV records represent a specific type of DNS record which works with specific services including FTP and SIP, and the way these specific services are used by a domain. Effectively SRV extends standard DNS record types to cater for different kinds of internet services. It explains how a specific domain will interact with a specific internet service, like FTP or SIP.
How SRV records are used
SRV records have a lot of different uses, but one common way to make use of SRV is to enable the location of the service endpoint for a specific domain with respect to different internet protocols, including XMPP and of course session inline protocol, or SIP, the protocol used for VoIP.
That’s why web browsers must be able to understand SRV records. Thanks to SRV records companies that provide specific services such as VoIP can specify the port and other system-specific information that enables a connection, all through a DNS record specific to a domain.
The format of a typical SRV record
SRV records are a long string of parameters that contain a number of common elements. First, there’s the name of the service, called “Service”; there is also the “Name” which is the domain name; furthermore there is a TTL and DNS class specification, plus “Priority” which specifies a target host priority. SRV also includes a relative weight for records of the same priority, specified with “Weight” plus a “Port” parameter which specifies the port the service is supposed to use. Finally, the “Target” parameter will specify the canonical hostname for a server which is delivering a service.