What do we want to archive
Install and activate the Uncomplicated firewall (UFW) and list some basic commands for adding and removing rules
Requirements
Debian, Ubuntu, etc
How do we get there
Installation:
#sudo apt install ufw
Default rules
The following defaults will allow all outgoing traffic, and block all incoming traffic, which will make for a nice set of defaults to start out secure:
# ufw default deny incoming
# ufw default allow outgoing
Doing this remote ? then you just might want to allow ssh before enabling these rules and locking yourself out.
#ufw allow ssh
Finaly, activate the firewall:
#ufw enable
Some handy commands
ufw status numbered | list the active set of rules, in a numbered format |
ufw allow 80/tcp | Allow specific port and protocol access |
ufw allow 53 | Allow all protocols on port |
ufw allow from 10.25.8.0/22 to any | Allow all traffic from a specific subnet (handy for local network) |
ufw delete 7 | Delete configured rule number 7 |