A firewall is a security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It serves as a barrier between your computer (or network) and external networks, such as the internet, to protect against unauthorized access and cyber threats.
Here’s how a firewall protects a computer:
1. **Traffic Filtering**: It inspects data packets traveling to and from your computer and blocks or allows them based on specific rules or criteria. This helps prevent malicious data from entering your system.
2. **Blocking Unauthorized Access**: It can block unauthorized users or applications from accessing your computer or network, preventing potential attacks or breaches.
3. **Monitoring Activity**: It tracks and logs network activity, providing alerts or reports on suspicious behavior or attempted intrusions.
4. **Restricting Access**: It can restrict access to certain applications or services, ensuring that only approved programs can communicate over the network.
5. **Implementing Policies**: It enforces security policies such as denying connections from untrusted sources or restricting outgoing traffic to prevent data leaks.
By filtering and controlling network traffic, a firewall helps protect your computer from various cyber threats and unauthorized access.