Murus menulet appears as an icon in OS X's menu bar. It displays the current PF status (packet filter). PF is an OS X built in network firewall. It is disabled by default. Murus Menulet allows you to monitor PF status and enable it using either the shell terminal or a third-party front end such as IceFloor, Murus Lite or PFLists. Murus Menulet is an app that allows you to use native Swift/Cocoa apps.