Which port number is commonly used by DNS for resolution queries?

The port number that is commonly used by DNS (Domain Name System) for resolution queries is 53. DNS is a critical part of the internet's functionality, allowing users to resolve domain names into IP addresses, which are necessary for routing traffic across the internet. When a device needs to look up a domain name, it sends a query to a DNS server, typically using the User Datagram Protocol (UDP) on port 53.

While DNS can also use TCP, particularly for tasks requiring larger packet sizes, such as zone transfers, the default and most frequent communication for resolving names occurs over UDP on this port. Understanding this concept is crucial for network configuration and troubleshooting, as DNS issues can lead to connectivity problems if the method of querying or the designated port are not handled properly.