If it uses the UDP protocol to send and receive data, it will use a UDP port. Figure 1, below, is a represenation of an IP address split into its many TCP and UDP ports.

Port Query (PortQry.exe) is a command-line utility in the Windows operating system that you can use to help troubleshoot TCP/IP connectivity issues.

Security practitioners for decades have advised people to limit DNS queries against their DNS servers to only use UDP port 53. The reality is that DNS queries can also use TCP port 53 if UDP port ...