Firewall Explained

A firewall is necessary to keep you safe on the internet. But what the heck is it and how does it work? Well, if you have known me for any length of time, you would know that I like to explain things in easy to understand analogies. Most likely I have explained something to you in your own language.

Firewall rules are recipes

For example, if you are a cook, I would say something like: “a firewall is like a recipe. A list of ingredients that are allowed in your stew.” Or, if you are a gardener, I’d say, “A firewall is like your weed killer. A substance that suppresses weeds and allows your roses to thrive.”

By now you might start to understand the answer to the question, “What is a firewall?”

The parable of the party

Imagine a door. Someone knocks and you open it. Your visitor is your son who happens to live in your house. Would you let your son in?  Why wouldn’t you? He’s your son – who lives there!

Now imagine you are having a party to celebrate your son’s birthday.  Your son is a popular kid and you get along well with your neighbors, so you invite all his friends and your neighbors.

As the neighbors arrive one by one, you open the door, identify your visitor and let them in.  When an unknown visitor arrives, you ask your son if this invitee is one of his friends.  When he affirms the identity of the visitor, his friend is allowed in.

Visitors make themselves at home as the day goes by. Eventually they (not you) begin to open the door to other potential guests.

Who polices the police?

Intruders, posing as guests, are able to bypass the guest list and get into your home. Once inside they begin to go through your rooms and private areas. They take liberties and pocket a few valuables. They feel so comfortable in your home that they make use of your phone to call more of their despicable friends.  The uninvited guests become the door guardians allowing anyone to come inside.

What can you do to protect yourself?

Whether you are having a party with a large guest list or it is just you and your family who are going in and out of the house, you need a way to keep track of “who” can use that door.

How do you manage your guests? What about your uninvited guests? Do you have an impenetrable steel door or a summer screen door?

What is a firewall?

A firewall is a method of keeping a damaging force from spreading from one side to the other. You’ve seen in movies. A fire starts in on side of a building and immediately a steel door shuts so the fire won’t spread. A software firewall is very similar.

In computers, a firewall is a program that manages the traffic of information going in and out of your computer. It inspects every packet of information for identification. If it is not identified, it stays out or in – depending on the direction of the flow.

Firewalls are (just) a set of instructions that dictate what happens.

Going back to your (out of control) party, you could have hired a guard that would hold a list of people who were invited. The rule would be, “If visitor is on the list, let them in. Otherwise, keep them out.”

The same is true for your computer. The firewall will keep a list of “things” that can travel into your computer or try to leave from your computer. Without a firewall a Trojan horse can penetrate your computer. Once inside, it can invite its friends. A properly programmed firewall would have a list of programs that are allowed to interact with your computer.

Back to your side of the fence

What kind of “firewall” do you use on a daily basis? Be creative.

Do you want to know more about firewalls? Please leave me a comment below.  I promise that I read every single comment.

Of course this article would not be complete without me inviting you to join my list. And if you know someone who might benefit from my “wisdom”, please share.

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  1. Juan, I’m presuming I have a firewall since you are my caretaker on this computer. Am I correct in thinking this? Good article too. very informative. Thanks. Bette

    1. All Firewalls are not the same. Some block traffic in from the internet if it’s not allowed. Others block uninvited traffic in both directions. The latter is better.

      Most people get in trouble because they click on buttons or links without reading and understanding the consequences. The firewall will only protect you if you give it the correct instructions.

      I believe the AVG firewall is better out of the box. A firewall properly configured is good no matter the brand.

      McAfee Personal Firewall should be okay as long as you have configured it properly.