How to Configure UFW Firewall Rules in Debian 12 Bookworm
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3 minute read
Introduction
Uncomplicated Firewall (UFW) is a user-friendly front-end for managing firewall rules using iptables. It simplifies firewall management by providing an easy-to-use interface while maintaining powerful functionality. Debian 12 Bookworm, like previous Debian releases, does not enable UFW by default, but it can be installed and configured quickly.
This guide provides a step-by-step process to install, configure, and manage UFW on a Debian 12 system to secure network traffic effectively.
Prerequisites
Before proceeding, ensure you have the following:
- A Debian 12 (Bookworm) system.
- A user account with
sudoprivileges. - Access to a terminal or SSH session.
Step 1: Install UFW
Debian 12 does not come with UFW pre-installed, but you can install it from the official repository using:
sudo apt update
sudo apt install ufw -y
After installation, check the status of UFW:
sudo ufw status verbose
If UFW is inactive, you will see an output like:
Status: inactive
Step 2: Enable UFW
Before enabling UFW, ensure that SSH access is allowed if you are configuring it remotely. Otherwise, you may be locked out of your server.
To allow SSH access:
sudo ufw allow OpenSSH
Now, enable UFW:
sudo ufw enable
Confirm its status:
sudo ufw status verbose
Expected output:
Status: active
Step 3: Configuring UFW Rules
Allowing Specific Services
UFW comes with predefined application profiles stored in /etc/ufw/applications.d/. To list available applications:
sudo ufw app list
For example, to allow HTTP and HTTPS traffic:
sudo ufw allow 'Apache Full'
Alternatively, you can specify individual ports:
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
Allowing and Denying Specific IP Addresses
To allow a specific IP to connect to all ports:
sudo ufw allow from 192.168.1.100
To allow an IP on a specific port:
sudo ufw allow from 192.168.1.100 to any port 22
To deny an IP address:
sudo ufw deny from 192.168.1.200
Allowing or Denying Port Ranges
To allow a range of ports, use the following syntax:
sudo ufw allow 1000:2000/tcp
sudo ufw allow 1000:2000/udp
Managing Incoming and Outgoing Traffic
By default, UFW blocks incoming connections and allows outgoing ones. To change this:
sudo ufw default deny incoming
sudo ufw default allow outgoing
To deny all outgoing traffic (use cautiously):
sudo ufw default deny outgoing
Step 4: Deleting or Resetting Rules
To remove a specific rule, first, list all rules with numbers:
sudo ufw status numbered
Then delete a rule by number:
sudo ufw delete <rule-number>
To reset UFW to its default state:
sudo ufw reset
Step 5: Logging and Monitoring UFW
Enable logging for better visibility into firewall activities:
sudo ufw logging on
To check firewall logs:
sudo journalctl -u ufw --no-pager | less
Step 6: Disabling UFW
If you need to disable UFW temporarily, use:
sudo ufw disable
To completely remove UFW:
sudo apt remove --purge ufw -y
Conclusion
UFW provides a straightforward way to manage firewall rules on Debian 12 Bookworm. By configuring UFW properly, you can enhance your system’s security while ensuring necessary services remain accessible. Regularly review firewall rules to keep your system protected from unauthorized access.
By following the steps in this guide, you now have a fully functional and secure UFW setup on Debian 12.
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