There are a lot of these sitting around

Which of these port numbers would be most associated with Mac OS file services?

A) tcp/445

B) udp/138

C) tcp/3389

D) tcp/20

E) tcp/548

F) I’ll just use whatever port happens to be closest

The answer: E) tcp/548

Port 548 over TCP is used for file services in Mac OS. Port 427 over both TCP and UDP is used for SLP (Service Location Protocol) to populate a list of available devices.

Want to know more? Watch “Common TCP and UDP Ports.”

We use transport-layer protocols to communicate to specific services on a remote device. In this video, you’ll learn about some of the most popular TCP and UDP ports used on our servers.