How Firewalls Work on Computer Networks

You may have heard of firewalls, but what exactly is a firewall? Does a firewall stop viruses? Can you not use a firewall? Actually, there is a possibility you use a firewall today - if your computer is running a modern operating system, there will be a firewall installed. Or perhaps, your security suite comes with a firewall. 

Curious about the understanding and how the firewall works? Check out the information below!

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What is Firewall

Firewall is a computer network security system that serves to protect computers from various types of viruses, malware, and attacks in other forms.

The main task of a firewall on a computer is to monitor and control all incoming and outgoing connections that you make based on predefined security rules.

In general, a computer firewall is a software program that prevents unauthorized access to or from a private network.

So, a firewall is a tool that can be used to increase the security of computers connected to a network, such as a LAN or the Internet. A firewall is also an integral part of a comprehensive security framework for the network you are using.

The Firewall function ensures security through the activation of granular control over the type of function. The firewall will also enforce system processes that have access to network resources.

Most people think that a firewall is a device that is installed on a network, and controls the traffic that passes through a network segment. However, you can also have a host-based firewall that can run on the system itself, such as ICF (Internet Connection Firewall).

Basically, the function of the two firewalls is the same: to stop intrusion and provide a strong method of access control policies. In simple terms, a firewall is nothing but a system that protects your computer; access control policy enforcement points.

Benefits of Firewalls for Computers

A firewall which is a barrier meant to protect your PC, tablet or phone from the dangers of data-based malware on the Internet has several benefits, namely:

  • Protect your computer from unauthorized remote access

One of the worst things that can happen to your computer is if someone tries to take control of it remotely. Seeing the mouse moves on the screen because the act of hackers is certainly frightening. With a properly configured firewall (and a modern OS), you can disable remote desktop access, preventing hackers from taking over your computer.

  • Can block messages that link to unwanted content

The internet has a lot of bad code traversing cyberspace, waiting to pounce on unprotected PCs. Firewalls can prevent this from happening.

  • Making online gaming safer

Any attempt by hackers to use their malware to get into your system will be blocked, making your system safe.

How Firewalls Work

When your computer has firewall protection, everything entering and leaving the computer will be monitored. The firewall monitors all information traffic to allow 'good data' to enter, and blocks 'bad data' from entering the computer. 

Firewalls use one or more of the three methods below to control traffic flowing into and out of the network:

  • Packet filtering

Packets (small pieces of data) are analyzed against a set of filters. Packets that pass through the filter are sent to the requested system, while other packets are discarded.

  • Proxy service

Through proxies, information from the Internet is retrieved by the firewall and then sent to the requested system and vice versa.

  • Stateful inspection

A newer method that does not check the contents of each package but compares certain key parts of the package with a trusted database of information.

Information from inside the firewall to the outside is monitored to determine specific characteristics, then the incoming information is compared with these characteristics. If the comparison results in a reasonable match, the information is allowed in. Otherwise, discarded.


That's information about the meaning of firewalls and their benefits and how they work. You should also use a firewall to make the network more secure. Hope it is useful!

Harbyj | Author

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