Security

Everything You Need to Know About Firewalls

By Kim Boatman

Connecting to the Internet without a firewall is a bit like parking your car in a rough neighborhood, and then leaving the doors unlocked, windows rolled down and keys in the ignition. As most of us know by now, the Internet can indeed be a risky neighborhood, and it’s important to protect your computer and your information from outside attacks.

A firewall is an integral component of home Internet security. Its job is to screen out hackers, viruses and worms that use the Internet to infect your computer with malicious code. Malicious code can destroy files and can cause malfunctions. A firewall also can help prevent others from stealing your personal information.

Your computer communicates on the Internet through ports that allow information to pass in and out. And therein lies the threat, says Mike Nadelman, a tech guru who owns San Francisco Computer Repair, which designs and implements computer networks and troubleshoots computer-related issues for businesses and homes.

“It’s like a house. You’ve got lots of windows and doors and ways to get things in and out of a house,’’ says Nadelman. “Some people lock their windows; some people leave them wide open. Firewalls basically lock certain windows and doors, and they leave others open with an emphasis on filtering what comes in and out of them.”

Protecting your computer can be confusing. It helps to know a few basics about firewalls:

1. How a firewall works.
   A firewall, which can be either software or hardware, controls the information that flows between your computer and the Internet. It filters the packets, or chunks, of information sent over the Internet, allowing only the data the computer is authorized to send or receive. It also prevents unauthorized connections to your computer by other computers, and a firewall can hide your computer’s unique IP address, making it “invisible” to others on the Internet.

2. How to know if you have a firewall.
   Most current Windows systems come with a firewall. To see if your firewall is turned on, click on the START menu, and then click on the control panel. Click on security center (look for the multi-colored shield). You’ll see a green indicator if the firewall is on. If you’re using Windows XP, points out security guru Joel Dubin, author of The Little Black Book of Computer Security (29^th Street Press), the firewall won’t block outgoing traffic. That’s significant because of the trend of bot-herding, in which outsiders access your computer, then use it to send spam or for other nefarious purposes.

The firewall in Windows Vista can block outgoing traffic. The vast majority of attacks are targeted toward Windows’ users, but Mac users can’t afford to be complacent. To check if your Mac firewall is on, go to Finder > Applications > System Preferences. In the System Preferences window that appears, says Dubin, click on the Sharing icon. You can open a firewall button and configure firewall preferences.

3. Hardware vs. software?
   A software firewall is installed on a single computer. It requires no additional hardware or wiring, but it uses computing resources. Other types of firewalls come in hardware devices. A hardware router is a physical box with multiple ports able to connect several computers to the Internet, but it requires wiring. Wireless routers are a type of hardware that allows you to connect multiple appliances, such as computers and personal desk assistants (PDA), to the Internet without wiring. If you are setting up a wireless network, then you want to make sure you purchase a wireless router with a built-in firewall.

“I would say that you should have a (software) firewall installed on your computer itself,’’ says Dubin. You can find free software firewall programs, but Nadelman advises caution. “A lot of people in their search for solutions will download fake stuff,’’ he warns. Don’t click on pop-ups or open emails offering free firewalls or other security-related programs. Be wary of fake programs sporting similar names to legitimate products. You’re safest sticking to security software from well-known companies or products from reputable web sites.

And consider using a wireless router, even if you have the software firewall, say the experts. Multiple layers of protection offer the most security.

4. Be ready to talk to your firewall.
   Some firewall programs will ask you about traffic between your computer and the Internet. A pop-up window might ask if you’ll block or allow the contact or allow it for just this one contact. The pop-up windows lessen as the program adds your instructions to the firewall rules.

5. A firewall isn’t enough on its own.
   You’ll still need anti-virus and anti-spyware software protection for emails and downloads. You’ll find security protection available in packages that include firewalls, anti-virus and anti-spyware functions, as well as in individual programs offering, for example, just a firewall.

Educating yourself before you prepare your computer’s defenses is essential, says Nadelman. “Do your research before you just download something that pops up on your screen. It’s important to do your research even before you turn your computer on.”