What DNS resource record type defines the hostname and port for specific services?

What DNS resource record type defines the hostname and port for specific services?

• A. A
• B. MX
• C. SRV
• D. AAAA

Answer: (C)

DNS SRV records specify the location of a specific service by including the hostname of the server and the port to reach it, along with optional priority and weight for choosing among multiple servers. This is exactly what you need when you want clients to connect to a particular service endpoint on a given port, rather than just an IP address. Other common records serve different purposes: A records map a name to an IPv4 address but give no port information; AAAA records map a name to an IPv6 address and also provide no port; MX records designate which mail server handles email for a domain and include a priority, but not the port for arbitrary services. In practice, SRV records are used for discovering service endpoints like SIP, LDAP, or other protocols that require knowing both the host and the port.

DNS SRV records specify the location of a specific service by including the hostname of the server and the port to reach it, along with optional priority and weight for choosing among multiple servers. This is exactly what you need when you want clients to connect to a particular service endpoint on a given port, rather than just an IP address.

Other common records serve different purposes: A records map a name to an IPv4 address but give no port information; AAAA records map a name to an IPv6 address and also provide no port; MX records designate which mail server handles email for a domain and include a priority, but not the port for arbitrary services.

In practice, SRV records are used for discovering service endpoints like SIP, LDAP, or other protocols that require knowing both the host and the port.