Ubuntu Linux server comes with a default firewall configuration tool i-e ufw. With ufw we can easily configure and use firewall rules on operating system. Command to check the status of the firewall. sudo ufw status verbose Command to start the firewall service and check the status . sudo ufw enable To allow incoming tcp packets on port 22. sudo ufw allow 22/tcp The command is as follows to open http and https service ports. sudo ufw allow http We can also leverage ufw service to check all the installed applications. sudo ufw app list
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