LuLu

What LuLu is

LuLu is a free, open-source firewall for macOS that alerts about and blocks unknown outgoing network connections. Alerts identify the process and destination, and can show code-signing details and process origins. Users can create rules to allow or block connections for a process or a specific remote endpoint, either temporarily or permanently. Allow and block lists can draw on local files or remote URLs; if both lists are configured, matching block-list entries take priority. Profiles keep separate rules and settings, but only the active profile is used to decide connections. LuLu monitors outgoing traffic, although some traffic may bypass macOS Network Extensions and consequently may not be visible or blockable. The listed requirement is macOS 10.15 or later. The app includes Objective-See’s Netiquette network monitor, which can be opened from the status-bar menu. A VirusTotal lookup opens only after the user clicks the alert button, and the lookup URL includes the item’s hash. The maker says the automatic version check sends no user or product information and can be disabled in settings.