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Erect A Firewall To Protect Your PC

Part of being a good user and consumer is understanding how technology works, why we use it the way we do, and what the barrage of acronyms and PR jargon means. We're here to help you make sense of it all and give you a better appreciation for how that pile of transistors, pixels, and antennas works together to deliver the conveniences of the modern world to your living room or office.

What is a firewall?

A firewall manages incoming and outgoing data for a PC or network. In order to keep out hackers and prevent the spread of malware, it monitors connections and applies a set of rules to either block or permit communications. A firewall can either be a program that runs on a computer or a dedicated piece of hardware that serves as a gateway for an entire network.

How does it work?

A firewall monitors connection attempts and either accepts or rejects these attempts at communication based on a set of rules. The rules and actual method for inspection are quite complex and come in a few different flavors. All, however, have the same basic set of functions at their heart. Think of a firewall like a border control check point. It stops each incoming packet of data (a packet is information bundled together to be processed in chunks) and determines whether or not to let the data through.

To understand how this works you'll first need to know that all Internet activity occurs via a set of communication protocols, such as TCP (Transmission Control Protocol), FTP (File Transfer Protocol) and SMTP (Simple Mail Transfer Protocol). In addition to defining what the data should look like, these methods of data transmission generally use a specific port number (a numbered channel for communicating with a computer). If you think of an IP address as a phone number, then a port number is like a direct-dial extension. One way a firewall determines whether a connection should be rejected is if a connection is made using a particular protocol, but is attempting to use a port other than the one your firewall is programmed to expect.

Why do I need one?

A firewall is an essential part of any PC's security arsenal. By locking down ports and rejecting certain traffic, it can bar hackers and prevent any malware you may have from passing your personal data to cybercriminals. Additionally, it can effectively quarantine an infected PC to keep it from spreading a virus to other computers on a network. In this way it is like a physical firewall (where did you think it got the name?) which prevents a fire from spreading and damaging adjacent property.

A good firewall will alert you to any unexpected attempts to communicate with your PC and ask you to allow or block individual programs as you "train" it to recognize the programs you use on a regular basis and how they behave.

Don't they sometimes cause problems?

It's true that firewalls can cause trouble for particular applications, but there are methods for bypassing it on a limited basis. The most common of these is port forwarding. Port forwarding directs all information targeted at a particular port to a specific program. For example, some games have trouble with a firewall's default settings. Setting up port forwarding for a game like 'Call of Duty,' then, ensures smoother online game play.

Most modern routers have a network-wide firewall and all the major operating systems have one on board. Windows XP users will want to use a third-party firewall, like Comodo, or one packaged with a security suite, such as Kaspersky. Windows Firewall, which comes with XP, is missing many important features and is far less secure than the versions available for Vista or Windows 7.

We're not gonna lie, firewalls are not the most exciting topic to read about. But understanding what they are and why they're so important to computer security is essential to being a good netizen. Securing your PC and data benefits not just you, but others who don't have to fear your computer will become just another cog in malware distributing botnet.

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