CompTIA A+ Core 2 (220-1202), Domain 4, Objective 4.9 focuses on remote access technologies, and this first article covers the tools that let a technician see and control a distant computer's desktop: Remote Desktop Protocol (RDP), Virtual Network Computing (VNC), and general-purpose screen-sharing software. These are the everyday workhorses of remote support, and the exam expects you to know which one fits a given scenario, what port each uses, and how they differ under the hood.
In this article you'll learn how RDP, VNC, and screen-sharing tools actually work, the ports and protocols they ride on, their strengths and limitations, and how to choose the right one for a help-desk ticket. We'll finish by comparing them side by side so you can answer scenario questions quickly.