What type of port is used by DNS for its operations?

Domain Name System (DNS) primarily uses UDP (User Datagram Protocol) for its operations. This is because DNS queries and responses are typically small in size and do not require the overhead associated with establishing and maintaining a connection, which is characteristic of TCP (Transmission Control Protocol).

UDP is a connectionless protocol, making it suitable for DNS, as it provides faster query and response times important for the quick resolution of domain names to IP addresses. When a DNS client, such as a web browser, sends a DNS query to a server, it generally uses UDP, as the request is usually a single message and the response is of a similar size.

While DNS can utilize TCP—particularly for tasks involving larger data sizes, such as zone transfers between DNS servers or in cases where the response data exceeds the size limitations of a UDP packet—these situations are less common, which is why UDP is the primary protocol associated with standard DNS operations.