What is a firewall?

A computer firewall is simply a hardware device or software program that allows into your computer only the programs and data you decide are acceptable. Firewalls are the best defense a computer can have. Simply put, a firewall detects, rejects, and protects.


How a firewall works
A firewall isolates your computer from the Internet by inspecting each piece of data - inbound or outbound - as it reaches the firewall. It uses certain basic rules to decide what goes through and what doesn't.

Each little package of data must correctly identify itself by specifying a destination address and a port number on that computer. It must also contain its originating address and the port number from which it was sent. Think of it as the address information on a regular envelope - both return address and recipient.

Since every data package contains this address information, a firewall can selectively accept or reject the various packages of data it receives. Certain rules specify which ports are valid destinations on your computer. Other rules specify which ports are valid senders from your computer.

Each data packages also contains a little snippet which states whether it is initiating a conversation or acknowledging one that is already taking place. Rules stipulate how data conversations can be initiated and how they must be acknowledged.

Your firewall knows which packages match its rules and are therefore acceptable. All other packages are refused delivery and go no further than the firewall.


Hardware firewall
A hardware firewall is an external device that resides outside your computer. A software firewall is a program that resides inside your computer.

Both types of firewalls analyze all incoming and outgoing traffic according to preset rules. You can also add additional instructions to your firewall that will allow certain types of additional communication.

Using a hardware firewall on a home computer is rare as they are designed to isolate and protect computer networks. In some cases though, you might use a hardware firewall at home.

Many people network their home computers together and connect to the Internet through a single, high-speed connection, usually cable or DSL. Several manufacturers include firewalls within the cable/DSL routers sold in most home electronics stores.

These hardware firewalls disguise everything behind them with their own unique addresses, called subnets. Communication like this uses Network Address Translation (NAT). NAT essentially hides you from prying eyes outside, just as if you were behind tall castle walls.


Software firewall
A software firewall performs the same functions as a hardware firewall. It places a wall of code in front of all data transmissions instead of a physical device that essentially contains its own wall of code.

Either type of firewall will provide the necessary castle walls you need for your computer. In addition, you'll need to strengthen your castle walls with antivirus protection, spam prevention, spyware removal software.


Free personal firewall
A free computer firewall provides security software that blocks trojans and worms on a cost-effective basis. Your software firewall is easy to install from a firewall download. You'll quickly have much needed firewall protection in place in less than five minutes.

Firewall software is a must to keep hackers out of your PC. Your firewall also provides a multi-layered defense against virus attacks. Get your protection in place BEFORE it's too late.


Where you can get a free firewall
Every computer needs firewall protection. Several companies make free personal firewalls available. The best one is Zone Alarm from Zone Labs.

Zone Alarm is a scaled down version of the top-selling Zone Alarm Pro. Millions of people use this award-winning security for Internet-connected PCs.

You can get their excellent free firewall, Zone Alarm, or a 30-day free trial of Zone Alarm Pro. Both keep hackers at bay with protection against worms, Trojans, spyware.

The Pro version also protects against 47 types of malicious email attachments. ZoneAlarm Pro includes Cookie Control and Ad Blocking for a faster, safer Internet experience.

Click here for Zone Alarm's Free firewall software

You know there's absolutely no sense in not keeping your computer and private data as safe as possible. Add firewall protection to your computer today.

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