How Firewall Works

By: Amber Newby | September 4, 2013 (Edited July 7, 2017)

how it works

Chances are you have heard the term "firewall" before. You most likely have heard about how it restricts you from going to a certain website and that it does something to protect your computer. All of this is true. It does somewhat "restrict" you, but it only does so to protect your information and your computer. Firewall protection is crucial, especially with so many cyber criminals lurking online.

What Is A Firewall?

A firewall is essentially what the name suggests, a wall of security that protects your computer from damage. A firewall is a software or hardware device that manages incoming and outgoing traffic from the internet to your personal computer. The traffic is analyzed by data packets which will determine whether or not something is to be flagged or if you can continue. The firewall barrier acts as a security separation between your computer (a secure internal network) and an outside network, like the internet, that is not necessarily secure.

What Does It Do?

To put it in simple terms, a firewall protects. Its job is to keep your computer secure. A firewall analyzes and monitors packets of data and then makes comparisons to determine whether or not it is safe to proceed. By using various strategies, firewalls can control the flow of traffic by analyzing and filtering information to and from your computer and the internet. When a packet is safe, your computer will allow you to proceed. If it is not, then it will be discarded.

How Does It Work?

If there is a firewall at every internet connection, rules can be set to limit what information a computer can access, making sure files and documents remain safe. To control the network traffic, a firewall will use stateful inspection, packet filtering, proxy service, or stateful inspection (and maybe even a combination of multiple methods) to ensure computer safety.

  • Packet Filtering
  • Small amounts of data, otherwise known as "packets," are compared to safe and trusted filters. Once the comparison has taken place, these packets are either permitted to go through the filters or they are discarded depending on the firewall analysis. If a packet is permitted to go through a filter, it will automatically be sent to the system that requested it.

  • Proxy Service
  • The proxy service simply takes information that is recovered by the firewall and is found on the internet and sends it to the requesting system.

  • Stateful Inspection
  • Stateful Inspection uses a comparing mechanism to determine whether or not certain parts of the packet can be trusted. Rather than going through and looking at all contents from each packet, Stateful Inspection compares important parts of the packet to a trusted database. Key elements in outgoing traffic are examined, and then incoming traffic is compared to those same elements. If there is reasonable similarity, the incoming traffic is permitted to come in. If not, that traffic is eliminated.

Customize Your Firewall

Firewalls allow you to configure your protection. Items that can be customized include: IP address, domain name, protocol, port or even specific words or phrases. This is a helpful tool because it allows you to strengthen areas of protection where you feel your computer may be the most vulnerable.

Why Is It Important?

You don't want your private information accessed or your files hacked. A firewall can prevent that from happening. The last thing you want is an unauthorized set of eyes on your information. Bank statements and online shopping records need to be kept private, but you need that extra security to make sure it safe. Without that layer of protection, your computer is susceptible to all sorts of threats and dangers.


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Written by Amber Newby

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