Hello again. Today I will tell you about controling the traffic to and from your Computer. So prepare to find out how to Install and Use a Firewall Program

You probably saw (at least in movies) people that have their houses surrounded by guards. Usually those guards greet every person that wants to enter. They politely ask every person on who want to see and ask for IDs. If all is okay, people pass through the guard’s checkpoint. That guard’s job is to assess everybody who wishes to enter or leave the property to decide if they should continue or be stopped. The guard keeps the unwanted out and permits only appropriate people and objects to enter and leave the business’s premises.

On a computer, the firewall acts much like a guard when it looks at network traffic destined for or received from another computer. The firewall determines if that traffic should continue on to its destination or be stopped. The firewall “guard” is important because it keeps the unwanted out and permits only appropriate traffic to enter and leave the computer. A computer connected to the Internet, without a firewall can be hijacked in just a few minutes by some automated programs (called bots).

To do the “guardian’s” job, the firewall needs to check every piece of information (called packet) that wants to enter or leave your home computer. Each packet is labelled with where it came from and where it wants to go. Some packets are allowed to go anywhere other packets not. It depends of permissions. Like a guard can let pass persons that are familiar with the property owner and can throw out an unknown one. If the firewall allows the packet to proceed, it moves the packet on its way to the destination. Usually, the firewall records where the packet came from, where it’s going, and when it was seen in log files. The guardian does it the same. But the guardian may do some more things before let a person enter. If the person is not on the allowed list, the guardian calls the property owner and asks for permissions. Sometimes the visitor may gain restricted access, so they need to be escorted. If the person has briefcase, the guardian can inspect their stuff before deciding if the person enters or not.

The computer firewall decides if a given packet should pass, allowing the computer’s user to respond to an unsolicited, unanticipated network traffic. The firewall “guard” is important because it keeps the unwanted traffic out and permits only appropriate traffic to enter and leave your home computer. Firewalls can be setup to allow or deny different types of files to access your home computer. Some firewalls have advanced capabilities that make it possible to redirect packets to different destinations and perhaps even have their contents concealed inside other packets (similar to the visitor being escorted). Finally, firewalls can filter packets based not only on their point of origin or destination, but also on their content (inspecting the briefcase of a person before being allowed to pass).

Firewalls can also recognize and record when a computer-to-computer connection ends. If the connection was temporary (like a visitor), the firewall rules can change to deny future similar connections until the system’s user authorizes. Finally, outgoing connections can also be filtered according to content.

Shortly, with a firewall you can control which packets are allowed to enter your computer and which are allowed to leave.

Here comes the hard part of this process. You have to decide the details of the packets that will be allowed to enter or exit to/from your computer. If your firewall supports content filtering, you have to decide which content will be allowed and which not.

You can start by allow NO access in or out. Good strategy this also called deny-all firewall strategy. It is impractical for most home computers. What helps you if nothing can enter/exit your home computer? You will learn very soon that you have to make some changes regarding this home computer security strategy. So you need to allow packets in and out only if they have acceptable identification and possessions using some well defined rules. Add the requirement that if you don’t meet the precise criteria for admittance, you don’t get in.

You can create firewall rules that allow traffic to pass without reviewing each packet each time. For example, you may choose to allow your Internet browsers to visit any web site. This rule would define the source of that traffic to be your browsers (Netscape Navigator and Microsoft Internet Explorer, for example) and the destination location to be any web server. This means that anybody using your home computer could visit any Internet website, as long as that web server used the well-known standard locations.

Like in Task 2 - Install and Use Anti-Virus Programs, you have to do some tests before you purchase any firewall program.

You have to take care about some things:

1. To see if your firewall let you set rules to software applications (programs). (Some of them set general rules. This means that all programs are allowed to connect to a network). You need to avoid general rules that turns into unchecked behaviours and security holes. So if you run more programs that make the same type of connection on the same host, be sure you know them and setup rules for each other.

2. Sometimes you might run programs that are allowed to connect to any location in internet on a specific port. For example web browsers are allowed to connect everywhere so you can be able to see any website you like. It is strongly recommended to reduce this type of connections. Your target is to make those programs to only connect to specific locations where possible.

3. Sometimes, you will make a connection to the same location ten times or as much you will need while you use your computer. Your firewall must permit you to make this connection permanent. This means that you will add a rule so your firewall will know to allow your connection all time you intend to do it. If you don’t use this often, you should define it like temporary location and your firewall will ask you every time if you allow it or not.

More of firewall programs allow you to make temporary connections by default by not including it into their rules list. If you need it permanent you have to add a new rule. If possible ALLOW ONLY TEMPORARY RULES.

You don’t need to be a security professional to improve your home computer security. You will learn how every program on your home computer uses the Internet and slowly you will start to build sets of rules that defines what traffic is allowed and which traffic not, into or out of your computer. Our advice: allow in and out ONLY what you agree with and deny EVERYTHING ELSE.

Later you might use exceptions to your rules. For example you might want that everyone that use your home computer to visit any websites except a few that you chose. The exception rules must be placed before the general rules. This means that the connections that are NOT allowed must be placed before the rules that allow all connections to any websites because firewall programs search their rules starting from the first through the last. When the firewall finds a rule that matches the packet being examined, the firewall honors it, does what the rule says, and looks no further. For example, if the firewall finds the general rule allowing any web site connections first, it honors this rule and doesn’t look further for rules that might deny such a connection. So, the order of firewall rules is important.

Many firewalls can be programmed to require a password before changing the rules. This extra level of protection safeguards against unwanted changes no matter their source, that is, you, an intruder, or another user. Before you assign a password to your firewall. Since this is another chapter here, i will explain it very short for the moment: use combinations of symbols and leters from your keyboard. Don't use names, birthdates and stuff like this. your password must have at elast 8 - 10 characters and mean NOTHING.

See you next week. Thank you for your audience so far. Below are some Discounted computer security products that i really recommend.