Which layer of the TCP/IP reference model does DNS belong to?

Which layer of the TCP/IP reference model does DNS belong to?

• A. Application layer
• B. Transport layer
• C. Network layer
• D. Data Link layer

Answer: (A)

DNS is a service used directly by applications to translate domain names into IP addresses, so it sits at the application layer of the TCP/IP model. It has its own protocol (the DNS protocol) and typically runs over UDP (port 53) and sometimes TCP (also port 53) when needed. Because its primary role is to serve applications with name resolution, rather than performing routing, addressing, or frame handling, it belongs in the application layer rather than the transport, internet, or link layers. For example, when your browser needs to find the IP of a site, it issues a DNS query and gets a response, enabling the application to proceed with the connection.

DNS is a service used directly by applications to translate domain names into IP addresses, so it sits at the application layer of the TCP/IP model. It has its own protocol (the DNS protocol) and typically runs over UDP (port 53) and sometimes TCP (also port 53) when needed. Because its primary role is to serve applications with name resolution, rather than performing routing, addressing, or frame handling, it belongs in the application layer rather than the transport, internet, or link layers. For example, when your browser needs to find the IP of a site, it issues a DNS query and gets a response, enabling the application to proceed with the connection.