rdesktop is an implementation of a client software for Microsoft's proprietary Remote Desktop Protocol (RDP).
License: Open Source
rdesktop is an open-source solution primarily focused on providing RDP support for Windows systems, making it lightweight and fast but limited in features. On the other hand, RealVNC is a more versatile remote access tool with a user-friendly interface and strong security features, making it suitable for various platforms but potentially slower in low bandwidth scenarios.