OpenSnitch application firewall for Linux

I've installed OpenSnitch, a GNU/ Linux port of the rather well known macOS application Little Snitch

Screenshot of OpenSnitch, src:

Here's how-to build and install against an already properly configured go1.10.4 linux/amd64—slightly adopted from

# system dependencies
sudo apt-get install git libnetfilter-queue-dev libpcap-dev protobuf-compiler python3-pip
# src
go get
cd $GOPATH/src/
git checkout master
go get -u
export PATH=$PATH:$GOPATH/bin
python3 -m pip install --user grpcio-tools
go get
cd $GOPATH/src/
# build and install daemon and ui
sudo make install
sudo systemctl enable opensnitchd
sudo service opensnitchd start
# had to manual build and autostart ui
cd ui
sudo /home/matthias/.local/bin/pip3 install -r requirements.txt
sudo /home/matthias/.local/bin/pip3 install .
cp opensnitch_ui.desktop ~/.config/autostart/

Some pointers:

tail -f /var/log/opensnitchd.log