What is a Firewall?

A firewall is a system that is designed to prevent unauthorized access from entering a private network by filtering the information that comes in from the internet. Its purpose is to create a safety barrier between a private network and the public internet, protecting the network from hackers and malicious traffic.

In a building structure, a firewall provides a barrier to contain a fire and prevent it from spreading to the other side. Similarly, a network firewall works by stopping harmful activity before it can spread into the other side of the firewall and cause harm to a private network.

A firewall works by filtering incoming network data and determining, based on its rules, if it is allowed to enter the network. These rules, also known as an access control list, are customizable and determined by the network administrator. The administrator decides what can enter and leave the network, granting or denying permission accordingly.

Firewalls can make rules based on various factors such as IP addresses, domain names, protocols, programs, ports, and keywords. For example, a firewall can allow or deny access based on specific port numbers. Incoming data using allowed port numbers can pass through the firewall, while data using denied port numbers will be denied access.

There are different types of firewalls. A host-based firewall is a software firewall installed on a computer to protect that computer only. It can be pre-packaged with operating systems or purchased as a third-party software. Antivirus programs may also have built-in host-based firewalls.

On the other hand, a network-based firewall is a combination of hardware and software that operates at the network layer. It is placed between a private network and the public internet, protecting the entire network. Network-based firewalls can be standalone products, built-in components of routers, or deployed in a service provider’s cloud infrastructure.

Many organizations use both network-based and host-based firewalls for maximum protection. The network-based firewall protects the entire network, while host-based firewalls provide individual protection for computers and servers. This ensures that even if harmful data gets past the network firewall, the host-based firewalls on each device will stop it.

In conclusion, firewalls are essential in today’s high-tech world to keep networks safe. They act as a barrier between a private network and the public internet, filtering incoming data based on customizable rules. By using both network-based and host-based firewalls, organizations can ensure maximum protection for their networks, computers, and servers.

As found on YouTube