Firewal and SSH

[KunalSin9h]

A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between trusted internal networks and untrusted external networks, such as the internet.

To secure a firewall in Ubuntu, you can use the built-in Uncomplicated Firewall (UFW), which is a user-friendly front-end for iptables. Here's a basic guide to set up and secure UFW on Ubuntu:

1. Install UFW if not already installed:

sudo apt install ufw

2. Enable UFW:

sudo ufw enable

3. Set default policies:

sudo ufw default deny incoming
sudo ufw default allow outgoing

4. Allow necessary services (example for SSH):

sudo ufw allow ssh

5. Allow other needed services (examples):

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

6. Check the status of your firewall:

sudo ufw status verbose

7. To further enhance security:

   • Limit SSH connections:

     sudo ufw limit ssh
     

   • Use specific IP addresses or ranges for certain services:

     sudo ufw allow from 192.168.1.0/24 to any port 22
     

8. Regularly update your system:

sudo apt update && sudo apt upgrade

9. Monitor logs for unusual activity:

sudo tail -f /var/log/ufw.log

Would you like me to explain or break down any part of this setup process?