Domain name resolution overview

DNS is the part of the TCP/IP protocol suite and, more specifically, it is a part of the application layer.

The following diagram shows the TCP/IP layer model, the TCP/IP protocol suite, and the DNS protocol position, among other protocols:

The DNS namespace is based on a hierarchical and logical model and uses a series of messages that are sent over either User Datagram Protocol (UDP) port 53 or TCP port 53. UDP is the primary protocol for DNS operations because it is faster.

The DNS consists of three main components:

• The domain namespace and resource records
• The nameservers
• The resolvers