To the new and improved levees that were built post Katrina and the guard rails that line a twisting mountain road, preventative structures have long been synonymous with the safety and security of the American people.  In the same sense computers and other electronics that house sensitive data have also taken to this notion and followed suite.  Enter anti-virus software, security suites and last but not least, firewalls.

Computer Housekeeping; Firewall 101

The idea of a firewall lends itself from the actual physical structure of the same name, but unlike the thick pieces of metal that protect passengers aboard a plane or the large wall of buildings that aim to keep a fire from spreading to nearby structures, a firewall in the computing world generally comes in the form of a piece of software.

As the internet became more and more widespread throughout the late 80s and early 90’s the need to keep information secure became a priority.   The 1990’s saw an increased number of PC’s becoming victim to what has now become known as cyber-attacks.  In order to combat these intrusions, the firewall was conceived.

A firewall is a piece of software or hardware, that once installed on a computer, acts as a gateway between information that is let in and information that is let out.  Picture the giant laser-eyed Sphnyx of the classic film, “The Neverending Story”.  Any intruder that didn’t pass a certain criteria was effectually “quarantined” and not allowed entry or exit.  Firewalls, much like these giant, fictional statues essentially do the same thing keeping any threats to your network’s security at bay.

Since its inception in 1988, firewalls have evolve and adapted as the landscape of computing has changed over the years.  Because of the different needs of a private network and the different security risks associated with each, four different varieties of a firewall have emerged as the first line of defense in keeping your file sharing and internet browsing safe.

The first breeds of firewalls to make their way into the world of computing are known as packet filter firewalls.  These varieties of firewalls are akin to a Sherlock Holmes or careful private investigator.  A machine running a packet loss firewall carefully inspects each data packet that enters or leaves the network.  The parameters for what are and what are not accepted is generally set out by the user.  Critics of this form of firewall site its steep learning curve and the propensity it has to become vulnerable to internet protocol deceptions.

The year of 1990 saw further innovation with firewalls and the creation of what has become called circuit-level gateway implementation.  This variety of firewall assesses the information received from a specific source.  Once this information has been read a decision is made on whether or not it is safe to enter or leave the network.  Information that is deemed safe is then free to travel back and forth between these connections without the need to be inspected each time.  Still, security compromises took place and often came at a result of a network being bombarded with thousands of unique addresses at once in effort to overload the gateway.

The next firewall innovation comes in the form of a proxy. A proxy firewall works by setting up the illusion of a network address, masking the true address of the machine accessing information through it.  A proxy is best described as a go-between.  Information that is put out and information that comes in must first travel through the proxy where the information is changed in such a way as to hide the identity of the user’s network.  While highly effective, these types of firewalls put a huge strain on system performance and are widely known to severely cut the speed of which information is accessed.

The last major firewall improvement came via the explosion of internet-based content.  This kind of firewall is aptly named as a web application firewall.  A web application firewall can take its form via a plugin, software installed on the computer or hardware that has been put in.  However the firewall is created the web application version creates a set of parameters for information accessed through HTTP addresses.  When information that is indicative of a system or network attack is processed, the threat is quickly labeled and blocked from entering the local network or computer.

A good firewall will generally make use of a few of these types in order to maintain the highest amount of security and safety possible.  In addition, most operating systems come equipped with a firewall in order to protect users from the most basic of threats.

If you are unsure what kind of protection your computer is currently operating behind, do a quick system check to see what firewall is active (this information is usually found under your system properties).  If you are currently running without a firewall or are unsatisfied with your current provider, the internet is teeming with big name companies offering free-trials as well just completely free versions of their products that are more than acceptable for the average consumer’s needs.