What Is a Firewall and How Does It Work?

What Is a Firewall and How Does It Work?

The term firewall is common enough. You’ve probably heard it mentioned several times before. However, unless you’re in the IT line or heavily invested in technology, there’s still more to understand how the workings of firewall and what it actually does for you and your business.

 

What Is a Firewall?

What Is a Firewall and How Does It Work?

Simply put, a firewall is a program or a hardware device which filters the information that is coming through the internet connection to your computer system or private network. For example, if there the incoming information is flagged by the filters determined by the firewall, that information will not be allowed to go through to your system.

A firewall is a safety mechanism which helps to protect your computers, especially within a large organization where valuable data could easily be corrupted if the proper precautions are not in place to keep it safe. Firewalls are very important to these large organizations. Very important.

Picture this scenario. You’re in a company with about 300 employees, Each of these employees will have their own work space and computer. This means the company has hundreds of computers on their hands, all of which have network cards that are connecting them to each other. On top of that, the company will also have one or more connections to the Internet through T1 or T3 lines.

What happens if there is no firewall in place for these hundreds of computers? It means that your sensitive and confidential company data is easily accessible to anyone on the Internet. Hackers who know what they are doing can easily probe your computers and make FTP connections, and all it takes is one opening for a hacker to get through and wreak havoc on your system.

 

How Does a Firewall Work?

A firewall can be placed at every connection to the internet and security rules can be implemented. The company will be able to set up these rules for FTP servers, web servers and more. On top of that, the company will also be able to control how its employees are connected to websites, and whether the files are allowed to leave the company over the network or not.

The firewall, in essence, gives the company tremendous control over how the people in the company use its network. Firewalls work by employing the use of three methods to help control traffic flowing in and out of the company’s network. These methods involve:

  1. Proxy Service – This is when information from the Internet is retried by the firewall before it is sent to the requesting system. This works vice versa.
  2. Packet Filtering – Packets refer to small chunks of data which gets analysed against a set of filters. The packets are only sent through the requesting system if they make it through the firewall’s filters. Anything that doesn’t make it through gets discarded.
  3. Inspecting the State – This method works by comparing certain key parts of the packet to the database of trusted information, instead of examining the state of contents in each packet. All the information which is travelling inside the firewall and out of it will be examined, monitored and inspected for certain defining characteristics. The incoming information is then compared to these characteristics, and will only be allowed through if it is a reasonable match. Anything that doesn’t match will be discarded.

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