Firewall
A firewall is a security system that monitors and controls network traffic. It acts as a barrier between your device or network and the internet, allowing safe data through and blocking harmful traffic. Firewalls help protect computers, phones, and networks from attacks and unauthorized access.
How it works
A firewall checks incoming and outgoing data based on security rules. If the data matches the rules, it is allowed through. If it looks suspicious or dangerous, the firewall blocks it. This process happens automatically and continuously in the background.
Why firewalls are important
Firewalls help prevent:
- hacking attempts
- malware and viruses
- unauthorized access
- data theft
They are an essential part of modern internet security.
Types of firewalls
- Network firewall — protects an entire network
- Software firewall — installed on a device (computer or phone)
- Hardware firewall — built into routers or separate devices
Many routers already include a basic firewall.
Firewall and everyday use
You use a firewall every day, even if you don’t notice it. Home routers, operating systems, and corporate networks rely on firewalls to stay protected.
A simple example
Think of a firewall like a security guard at a building entrance. Only approved people can enter — everyone else is stopped.
Related terms
- What is Router?
- What is IP Address?
- What is VPN?
Source
Information simplified from the Wikipedia article “Firewall (computing)”.