Key Takeaways
- A Firewall filters traffic between your device and the internet.
- It can be Hardware (in your router) or Software (in Windows/macOS).
- It blocks unauthorized access to your computer's "Ports".
- Always keep your Operating System firewall turned ON, even behind a router.
It is the first line of defense in network security. But how does it actually work?
The Guard at the Gate
A Firewall monitors incoming and outgoing network traffic based on predetermined security rules. It establishes a barrier between your trusted, secure internal network and the unsecure external network (the Internet).
Types of Firewalls
- Software Firewall: Installed on your computer (like Windows Defender). It protects only that single device by monitoring applications.
- Hardware Firewall: Built into your router. It protects every device connected to your Wi-Fi by blocking bad traffic before it even reaches your laptop.
- Cloud Firewall: Protects servers and websites from the cloud (like WAF - Web Application Firewall).
Packet Filtering
Most basic firewalls inspect "packets" of data. If a packet comes from a blocked IP or tries to enter a closed port (like closing a door in your house), the firewall drops it immediately.
Frequently Asked Questions (FAQ)
Do I need a firewall if I have an antivirus?
Yes. Antivirus scans files for malware. Firewalls scan network traffic for intruders. You need both for complete protection.
Why does Windows Firewall ask for permission?
When you install a new game or app, it asks to "allow access". It is asking the firewall to open a specific port so the app can talk to the internet. Only allow apps you trust.
Is your network exposed?
Test Open Ports