UFW

Uncomplicated FireWall

Installation

sudo apt install ufw

Configuration

sudo ufw default deny incoming
sudo ufw default allow outgoing

sudo ufw allow 22/tcp    # SSH
sudo ufw allow 80/tcp    # HTTP
sudo ufw allow 443/tcp   # HTTPS

sudo ufw enable
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9