UFW, or Uncomplicated Firewall, is an interface to iptables
Prerequisites
To follow this tutorial, you will need:
UFW is installed by default on Ubuntu. If it has been uninstalled for some reason, you can install it with sudo apt install ufw.
$ sudo nano /etc/default/ufw Then make sure the value of IPV6 is yes.
$ sudo ufw default deny incoming
$ sudo ufw default allow outgoing$ sudo ufw allow ssh$ sudo ufw allow 22$ sudo ufw enable$ sudo ufw allow 80$ sudo ufw allow 443$ sudo ufw allow 6000:6007/tcp
$ sudo ufw allow 6000:6007/udp$ sudo ufw allow from 203.0.113.4$ sudo ufw allow from 203.0.113.4 to any port 22$ sudo ufw allow from 203.0.113.0/24$ sudo ufw allow from 203.0.113.0/24 to any port 22$ sudo ufw deny http$ sudo ufw deny from 203.0.113.4$ sudo ufw status numbered$ sudo ufw delete 2$ sudo ufw delete allow http$ sudo ufw delete allow 80$ sudo ufw status verbose$ sudo ufw disable$ sudo ufw reset
