LuLu

LuLu is a free, open-source outbound firewall for macOS developed by Patrick Wardle through Objective-See, a respected nonprofit organization dedicated to creating free security tools for Apple users. Released as a lightweight alternative to commercial firewalls like Little Snitch, LuLu provides essential protection against unauthorized outgoing network connections without the premium price tag. The application leverages Apple's modern Network Extension framework to intercept connection attempts, presenting users with immediate alerts when applications try to communicate with external servers. Designed with simplicity and transparency in mind, LuLu integrates VirusTotal malware scanning directly into its workflow, allowing users to check suspicious destinations against one of the world's largest malware databases before granting network access. Unlike complex enterprise firewalls, LuLu focuses on doing one thing exceptionally well: alerting users to outbound connection attempts and letting them decide whether to allow or block each connection. This makes it particularly appealing to privacy-conscious users, students, and security researchers who need reliable network monitoring without investing in expensive commercial solutions. The software receives regular updates from Patrick Wardle, a renowned macOS security researcher, ensuring it remains compatible with the latest macOS releases including Sonoma, Sequoia, and the upcoming Tahoe.