Is there a Linux application similar to Little Snitch? Little Snitch is an outgoing firewall that temporarily blocks outgoing network requests until the user decides whether to allow the connection or not. The most powerful feature of Little Snitch is that it is able to tell what host name each application wants to talk to and make permanent or temporary blocking rules based on host name or application. All of this in a really easy and convenient UI.
Leopard Flower is currently your best bet. You'll have to compile it from source though.
Someone here asked the same question and got essentially the same response: Recommended reverse firewall applications for linux?