Configuring Firewall Settings with ufw in Ubuntu

This article explains firewall configuration in Ubuntu. We introduce the basic usage of ufw.

• General commands status, enable, disable, reload, delete, allow, deny, default (allow|deny)

• First enable it

sudo ufw enable

• Disable it when not needed as it’s dangerous.

sudo ufw disable

• Based on the list displayed by status, you can insert or delete rules.

sudo ufw delete 2

• Delete all

sudo ufw reset

• When there are many rules, numbering is convenient

sudo ufw status numbered

• Example of allowing access to 22/tcp

sudo ufw allow 22/tcp

• Example of allowing access to 22/tcp from 192.168.3.9

sudo ufw allow from 192.168.3.9 to any port 22 proto tcp

• It seems you can also specify Ubuntu services like servers

sudo ufw app list
ufw allow from 192.168.1.0/24 to any app Samba

References:

• (https://www.cyberciti.biz/faq/how-to-open-firewall-port-on-ubuntu-linux-12-04-14-04-lts/)[https://www.cyberciti.biz/faq/how-to-open-firewall-port-on-ubuntu-linux-12-04-14-04-lts/]
• (https://help.ubuntu.com/community/UFW#Delete_Existing_Rule)[https://help.ubuntu.com/community/UFW#Delete_Existing_Rule]