FirewallsThis week we will talk about firewalls. I hope to give you some insight on how they work and some requirements that you should consider.

Firewalls 101

A firewall, by definition is software or a piece of hardware the screens out viruses, hackers and worms that can infect your PC. Why do you need a firewall on your computer?  Take a look…

It would make sense that if you have anti-virus software and you keep it current you would not need a firewall.  Unfortunately, this is not true. Here are some reasons why.

  • Viruses begin to spread before they are identified.  The only way they are detected is when you discover erratic behavior on your PC.
  • Firewalls block most of the viruses, Trojans, worms, and hackers trying to gain access to your your computer.
  • It’s possible that some vulnerability may not be patched before an attack occurs.  Firewalls prevent these attacks from being successful.

There is no guarantee that your system will be protected from viruses, worms and hackers, so you should keep copies of your data.  It’s a good idea to keep multiple backups on different media types.

There are two basic elements of a firewall.

Address – An address is basically a set of numbers ( better known as an IP address.  This number is used on a network to identify your PC by using a unique number.  Think of this number as your home address used by the post office so they can find the right house, making sure you get the correct mail.

Port – A port acts as an identifier of the programs that are running on a receiving computer and will process the information received.   Think of a port as a filter where the data must pass. If it doesn’t pass, it will be denied.

There are two main functions of firewalls.

Packet Filtering – This function allows information to be sent through or prevents the information from getting to the computer with specific programs that may have processed it.   Many corporations use this type of firewall. They filter traffic on a set of rules governed by the Network Administrator. In addition, they filter information based on both port and address.

Application Filtering – This function keeps a list of computer programs that can receive and transmit information across the Internet.  If the program is not given permission, the firewall will not allow access.  Most personal firewalls work this way.  This is why these types of firewalls can prevent adware and spyware since the program has no permissions and cannot download any additional programs.

Configure your firewall before connecting to the Internet.  Some programs may not function correctly when the firewall is enabled.  You might need to disable the firewall temporarily until the program is identified by the firewall.  When this is completed, enable the firewall immediately.

Please feel free to forward this information to others.  If you would like to learn more on this topic or would like to request an area of technology you are interested in, please send me an email.

Until next time…Happy Computing!!!

About Michael DeFlorio
I have worked is various positions as a system administrator, support technician, as a help desk support, and as an IT consultant in a corporate environment. I currently run a small business where I provide computer services such as hardware configuration, installation, for residential and for medium and small businesses. You can contact me by email or visit my website at

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