Uncomplicated Firewall (UFW) is a powerful yet user-friendly command-line tool that simplifies firewall management on Ubuntu and Ubuntu-based distributions. It allows you to quickly create and manage rules for controlling incoming and outgoing traffic on your system, ensuring your system is protected from unauthorized access. This article will guide you through setting up UFW on Ubuntu and using it to secure your system.
Installing UFW on Ubuntu
While UFW is typically preinstalled on Ubuntu, it might be absent in minimal or stripped versions. To ensure UFW is installed, run the following command in your terminal:
sudo apt install ufw
This will download and install UFW on your system.
Enabling and Configuring UFW
After installation, verify that UFW is active by checking its status:
sudo ufw status
If UFW is not active, enable it with the following command:
sudo ufw enable
Supporting IPv6
If your network supports IPv6, ensure UFW is configured to handle both IPv4 and IPv6 traffic. Open the UFW configuration file:
sudo nano /etc/default/ufw
Inside the file, locate the line IPV6=no and change it to IPV6=yes. Save the file and exit the editor.
Creating Firewall Rules
UFW allows you to create rules to allow or deny traffic based on ports, protocols, and applications.
Allowing Specific Ports
To allow traffic on specific ports, such as ports 80, 443, and 22 for Apache and SSH services, run the following commands:
UFW provides built-in application profiles that simplify the process of creating rules for common services. For example, to allow traffic for the HTTP/HTTPS protocol (ports 80 and 443) and the default SSH port (port 22), use:
sudo ufw app info "Apache Full"
sudo ufw app info "OpenSSH"
To view the current firewall rules, use the following command:
sudo ufw status verbose
To remove a firewall rule, first identify its index number using:
sudo ufw status numbered
sudo ufw delete14
To restrict access to the SSH port and prevent unauthorized attempts, use:
sudo ufw limit ssh
To make your firewall rules more understandable, add comments explaining the purpose of each rule. For instance, to allow access to a Portainer service running on port 8080:
sudo ufw allow 8080 comment 'Portainer Service'
UFW allows you to control connections from specific IP addresses.
Allow connections from a specific IP address:
sudo ufw allow from <IP address>
Allow connections from a specific IP address to a particular port:
sudo ufw allow from <IP address> to any port <port number>
You can also deny connections from specific IP addresses or to specific ports:
Restrict all connections from a specific IP address:
sudo ufw deny from <IP address>
Restrict connections from a specific IP address to a particular port:
sudo ufw deny from <IP address> to any port <number>
If you need to reset your firewall rules to their default settings, use:
sudo ufw reset
Disabling UFW
To temporarily disable UFW, run:
sudo ufw disable
UFW provides a straightforward way to secure your Ubuntu system by managing firewall rules. Its user-friendly interface and intuitive commands make it accessible to both beginners and experienced users. By following the steps outlined in this guide, you can confidently implement basic and advanced firewall configurations, ensuring your system is protected from unwanted traffic and potential security threats.
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