Set up firewall
# Block all incoming connections by default
sudo ufw default deny
# Enable firewall
sudo ufw enable
# Allow SSH connections from a specific subnet
sudo ufw allow from 192.168.1.0/24 proto tcp to any port ssh
sudo ufw status
Allow all traffic on a certain port
# TCP/UDP
sudo ufw allow 3389
# TCP only
sudo ufw allow 22/tcp
# TCP/UDP
sudo ufw allow from 192.168.1.0/24 to any port 3389
# TCP only
sudo ufw allow from 192.168.1.0/24 proto tcp to any port 22
Show firewall rules as a numbered list
sudo ufw status numbered
Delete firewall rules by number
sudo ufw delete 1