• https://www.digitalocean.com/community/tutorials/ufw-essentials-common-firewall-rules-and-commands
• https://linuxize.com/post/how-to-setup-a-firewall-with-ufw-on-ubuntu-20-04/
• https://wiki.archlinux.org/index.php/Uncomplicated_Firewall

• Ubuntu

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sudo ufw status

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sudo ufw status numbered

sudo ufw app list

Test

• Change x to an app listed in above command

sudo ufw app info x

sudo ufw app info 'CUPS'

• TODO: What does limit actually do?

sudo ufw limit ssh

• 22 is the port number and tcp is the protocol
• udp can be a protocol

sudo ufw allow 22/tcp

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sudo ufw reset && sudo ufw default deny && sudo ufw logging off && sudo ufw allow 'ssh' && sudo ufw limit 'ssh' && sudo ufw enable && sudo systemctl enable 'ufw'