What ports does DNS commonly use?

DNS, or Domain Name System, is a fundamental component of internet infrastructure used to translate human-readable domain names into IP addresses that machines can understand. The standard ports used by DNS are TCP and UDP port 53.

UDP is primarily used for DNS queries because it allows for faster transmission of data for short, simple requests without the overhead of establishing a connection. Since DNS queries often involve sending small packets, UDP's connectionless nature is beneficial for performance.

However, TCP is also utilized by DNS in specific scenarios, such as when the response data size exceeds the limits of a single UDP packet, or for tasks requiring reliable transmission, such as zone transfers between DNS servers. Both protocols operate over port 53, making this port the common denominator for DNS communication.

Understanding the functionality of both TCP and UDP in DNS operations emphasizes the importance of port 53 as it serves as the main conduit for the majority of DNS traffic.