Uncover the infinite in IT

How Can We Help?
Table of Contents
< All Topics

ufw

1. Installation:

If ufw is not already installed on your system, you can install it using the package manager for your Linux distribution. For example, on Ubuntu/Debian:

sudo apt update
sudo apt install ufw

On CentOS/RHEL:

sudo yum install ufw

2. Basic Commands:

Enable UFW:

To enable the firewall:

sudo ufw enable

This will also start ufw at boot.

Disable UFW:

To disable the firewall:

sudo ufw disable

Reset UFW:

To reset UFW to its default settings:

sudo ufw reset

3. Managing Rules:

Allow Connections:

To allow connections on a specific port (e.g., SSH on port 22):

sudo ufw allow 22

To allow connections from a specific IP address to a specific port (e.g., allow SSH from 192.168.1.3):

sudo ufw allow from 192.168.1.3 to any port 22

To specify a protocol (e.g., TCP):

sudo ufw allow from 192.168.1.3 to any port 22 proto tcp

To allow a range of ports:

sudo ufw allow 8000:9000/tcp

To allow a specific IP address:

sudo ufw allow from 192.168.1.2

Deny Connections:

To deny connections on a specific port:

sudo ufw deny 8080

To deny a specific IP address:

sudo ufw deny from 192.168.1.3

Delete Rules:

To delete a rule:

sudo ufw delete allow 22

Application Profiles:

ufw supports application profiles. For example, to allow HTTP traffic:

sudo ufw allow 'Nginx Full'

To see a list of available application profiles:

sudo ufw app list

4. Checking Status and Logs:

Check Status:

To check the status of ufw:

sudo ufw status

To view more detailed information:

sudo ufw status verbose

Viewing Logs:

ufw logs are typically available in /var/log/ufw.log:

cat /var/log/ufw.log

You can also use the journalctl command on systems using systemd:

journalctl | grep UFW

5. Default Policies:

Set Default Policies:

You can set the default policies for incoming and outgoing traffic:

sudo ufw default deny incoming
sudo ufw default allow outgoing

Conclusion:

Remember to adjust these examples based on your specific needs and requirements. The examples above provide a basic introduction to ufw usage. Always be cautious when configuring firewall rules to avoid locking yourself out of your system. It’s recommended to test rules in a safe environment before applying them in a production setting.