Ufw
ufw(8) (Uncomplicated Firewall) is a firewall management program. It is a wrapper around iptables(8).
Contents
Installation
Several Linux distributions offer a ufw package. Then start and enable ufw.service.
Configuration
A basic rule set is:
ufw default deny incoming ufw default allow outgoing ufw allow 22
ufw(8) is distributed with app profiles that simplify the configuration process. Instead of allowing ports, consider allowing apps.
ufw allow ssh
Web Servers
The following rules should allow any web server to operate.
ufw allow http ufw allow https
Additional steps may be required if using certbot on a custom port.
FTP
ufw allow 20/tcp ufw allow 21/tcp ufw allow 989/tcp ufw allow 990/tcp
Passive configuration also utilizes a pool of ports. Recommended to use custom ports, so adjust as needed.
ufw allow 40000:42000/tcp