The dialog also allows the user to restrict the parameters of the connection, restricting it to a specific port, protocol, or domain. For that, a dialog is presented to the user, which allows one to deny or permit the connection on a one-time, time limited, or permanent basis. If an application or process attempts to establish a network connection, Little Snitch prevents the connection, if a rule for that connection has been set by the user.

Until Little Snitch 4, it controled network traffic by registering kernel extensions through the standard application programming interface (API) provided by Apple, but for its 5th release it switched to using Apple's Network Extensions due to the deprecation of Kernel Extensions on macOS Catalina.

Unlike a stateful firewall, which is designed primarily to protect a system from external attacks by restricting inbound traffic, Little Snitch is designed to protect privacy by limiting outbound traffic. It is produced and maintained by the Austrian firm Objective Development Software GmbH. It can be used to monitor applications, preventing or permitting them to connect to attached networks through advanced rules.

Little Snitch is a host-based application firewall for macOS.

Little snitch for mac 10.10.5