LuLu

LuLu is a free, open-source firewall for macOS that blocks unrecognized outgoing connections until user-approved. It was designed to detect malware through unauthorized networking connections, but can also prevent OS components and third-party apps from transmitting data to remote servers. LuLu does not contain ads, time trials, or missing features, and does not track or monitor users. Its source code is available on GitHub for transparency and auditing. LuLu alerts users to unauthorized network connections, enabling malware detection and blocking of apps that may transmit private data. It prioritizes simplicity over complex features, making it user-friendly with a smaller attack surface. For businesses, LuLu provides simple mechanisms to track network events and maintains data such as rules in an accessible format.