UFW (Uncomplicated Firewall) provides a simple way to manage your system’s firewall using straightforward commands. It acts as a frontend to iptables, allowing you to define rules without dealing with complex syntax. Here’s how to add, edit, and delete rules using UFW.

Adding rules

To allow or deny traffic, you can specify ports, protocols, or applications. Examples:

# Allow incoming SSH traffic (port 22)
sudo ufw allow ssh

# Allow HTTP and HTTPS
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp

# Deny a specific port
sudo ufw deny 25/tcp

You can also limit connections to reduce brute-force attacks:

sudo ufw limit ssh

After adding rules, reload UFW to ensure they’re active:

sudo ufw reload

Viewing rules

To list all active rules:

sudo ufw status numbered

The numbered option is helpful when you want to edit or delete rules by index.

Deleting rules

You can delete rules either by description or by number.

# Delete by description
sudo ufw delete allow 80/tcp

# Delete by number (from `ufw status numbered`)
sudo ufw delete 2

After deletion, reload UFW:

sudo ufw reload

Editing rules

UFW doesn’t support direct rule editing. Instead, delete the old rule and add a new one. For example, if you want to change port 8080 access from “allow” to “deny”:

sudo ufw delete allow 8080/tcp
sudo ufw deny 8080/tcp

Summary

• Add rules with ufw allow or ufw deny.
• List rules with ufw status numbered.
• Delete rules by description or number.
• Edit rules by deleting and re-adding them.

UFW simplifies firewall management without sacrificing control, making it ideal for servers and desktops alike.

Resources

• UFW Essentials: Common Firewall Rules and Commands for Linux Security