If you’re studying for the CompTIA A+ exam, port numbers are one of those topics you absolutely cannot skip. They appear in the Networking domain of Core 1 (220-1201), which carries a 20% weight — and they show up in scenario-based questions that test whether you understand why a protocol uses a specific port, not just what the number is. This guide breaks down every port number the exam expects you to know, explains what each protocol actually does, and shows you how to study them in a way that sticks.
Why Port Numbers Matter on the CompTIA A+ Exam
Port numbers are how your operating system knows which application should receive incoming network traffic. When data arrives at your computer, the port number tells the OS:
Ready to Pass Your Certification?
Practice with 310+ expert-written questions across CompTIA A+, ISC2 CC, and SSCP.
Free to start — no credit card required.