Ubuntu Firewall settings - open, close, open port numbers

1, open ubuntu firewall

sudo ufw enable

2. Turn off the firewall

  sudo ufw disable

3. Check local port usage

sudo ufw status

4. Open the desired port (9000 for example)

sudo ufw allow 9000

5. Uninstall iptables (firewall)

 sudo apt-get remove iptables

6. Close ubuntu firewall in the rest of the command

    iptables -P INPUT ACCEPT
    iptables -P FORWARD ACCEPT
    iptables -P OUTPUT ACCEPT
    iptables -F