Little Snitch is a traditional software firewall for macOS. You can use it to monitor applications, preventing or permitting them to connect to attached networks through advanced rules. OpenSnitch is a GNU/Linux port of the Little Snitch application firewall written in Python.
The software is still in early stage of development, and alpha quality software, don’t rely on it (yet) for your computer security. However, this software can be very useful for Linux desktop users.
Install required software using apt-get command:
$ sudo apt-get install build-essential python-dev python-setuptools libnetfilter-queue-dev python-qt4 python-gtk2
Clone the repo:
$ git clone https://github.com/evilsocket/opensnitch.git
$ cd opensnitch
$ sudo python setup.py install
$ sudo opensnitch
The Little Snitch application firewall will start working immediately and will show dialog as follows:
You can allow, deny or whitelist apps. I hope the author will continue work on this app and releases a beta and stable version for the good of GNU/Linux users. For more info visit project home page here.