You can use Ubuntu Fire Wall. Block all ports and accept TCP UDP code example
Example 1: ufw allow port
sudo ufw allow http
sudo ufw allow 80Example 2: allow ip through ufw
sudo ufw allow from 15.15.15.0/24 to any port 22sudo ufw allow http
sudo ufw allow 80sudo ufw allow from 15.15.15.0/24 to any port 22