There are several ways to connect to remote machines. VNC is a lightweight open source protocal (typically runs on port 5900) to project the desktop of a system configured with a VNC service to any system that runs a VNC client. Typically all VNC clients see the same desktop - best when only one person needs remote access at a time.

Alternatives to VNC include Microsoft Terminal Server (Win32), X Windows (Linux, UNIX), and Apple Remote Desktop (MacOS).