What and Why
Internet Security
- How visible is my computer?
- What is a Firewall?
- Do you need a Firewall?
How visible is my Computer?
For most of us, the Internet is something of a mystery. We're not certain how it all works, and we don't know exactly how visible we are as we move around its virtual domain. Many of us are online all the time, exchanging information with friends and associates, doing research, reading the news. Naturally, we all wish we knew a little more about our day-to-day exposure. Who hasn't asked these questions: What aspects of my computer are visible to others? What parts can they access or manipulate? Are my emails and instant messages protected from prying eyes? Can anyone see what I'm doing while I'm on the Web? Of course, responses to these questions vary depending on your situation. But fortunately there are some general answers, and equipped with a little knowledge and protection, you can create a comfort zone for yourself on the Web.
What is a Firewall?
Firewalls function by providing a line of defence between computers that share information. The purpose of a personal firewall is to control the flow of information back and forth between your computer and your web server. A firewall examines all traffic routed between your computer and the Internet to see if it meets certain criteria. If it does, it is allowed in. If it doesn't, it is stopped, protecting your computer from intrusion, the firewall keeps your machine from getting burned by destructive intrusions that could result in data loss or file corruption. A firewall can give you the tools you need to protect your private information while connected to a public network. You may select which information you would like to protect, such as a credit card number or password. If you attempt to send that number to an insecure site - such as one that doesn't support sufficient encryption,the firewall will alert you. Firewalls can also prevent Web servers from getting access to other sensitive data, like your address, while you're browsing. Cookies, small text files stored on your computer by a web server, can be useful for surfing because they help other sites remember you when you revisit, eliminating the need to enter login information with each visit and keeping your shopping basket current. But they may also raise privacy concerns since they could be used to track your web surfing unknowingly.
Do you need a Firewall?
Personal firewalls are the best way to protect your computer against malicious attacks. They act as sentinels, keeping constant watch over your Internet connection and interrogating anyone who tries to access your computer. They ask "Who are you, and what's the password?" and they grant access only when they're satisfied with the response. More technically, personal firewalls monitor all incoming and outgoing traffic on your computer. They check each bundle of data, or packet that attempts to cross from the Internet to your computer, and vice versa. Every data packet has a signature identifying who sent the packet and how the packet should be processed. Firewalls look at this information and then make access decisions for you. They base these decisions on pre-determined firewall rules. If a packet is of unknown origin or doesn't fit a rule, the firewall will prompt you to make a decision. Beyond their basic duties, personal firewalls monitor and cloak ports to frustrate port scanning techniques. Essentially, personal firewalls keep the unwanted out, let the desirable in, and keep watch for suspicious activity. They're kind of like a private computer bouncer.