Think of your computer’s security like your home. The firewall is the lock on your door. Ubuntu’s default setup is like having a deadbolt—safe and sturdy. But sometimes you want to leave the door cracked open for fresh air (or for a friend to sneak in a pizza). That’s disabling the firewall temporarily.
You wouldn’t leave it open for a week while you go on vacation, right? Same with the firewall. Use it as a temporary tool, not a permanent lifestyle. It’s fun to experiment, but don’t get too comfy with the unlocked door.
