What it does
LuLu is a free open-source macOS firewall that blocks unknown outbound connections and lets users decide how applications may connect.
LuLu is useful when a Mac user wants a decision point for an unfamiliar outgoing connection. Its official instructions explain the macOS system-extension and network-filter approvals needed during installation. Work through those permissions deliberately, then review which applications need access. The project recommends current macOS updates because it relies on Apple's network-extension framework. That platform dependency matters when troubleshooting a blocked or unexpected connection.
Strengths
- Unknown outbound-connection control
- Detailed macOS permission guidance
Best for
- Mac users who want to review application network access
Sources
- Objective-See: LuLu (Oct 26, 2026)
- LuLu LICENSE (Oct 26, 2026)