Dentistry Today Computers Firewalls: Internet Security for Your PC, Peace of Mind for You
Computers

Firewalls: Internet Security for Your PC, Peace of Mind for You

  • June 1, 2002
  • 7 minutes read
  • 23 years ago

So, you just got a broadband (cable or DSL) Internet connection. I bet you love it; no more waiting for your dial-up modem to connect to your ISP (Internet Service Provider), or wasting time for downloads. Of course, this is assuming you don’t get disconnected in the process. Yes, the joys of dial-up are over for some, but broadband users have other problems associated with having a constant 24/7 connection to the unforgiving Internet. An unprotected computer connected to the Internet via broadband is like leaving your car running with the doors unlocked and the keys in it. A broadband Internet connection is easier to hack because it is “always on” and often has a static IP (Internet protocol) address. This means that once a hacker finds your computer, it is easier to find it again. Most 56k dial-up Internet connections use a new IP address each time you connect, which makes it much harder to find your computer again unless a Trojan horse program has invaded your system, which can phone its home each time you connect. Yet, there are many daily attempts by outside programs and websites to access your computer, no matter what type of Internet connection you use.


Security and privacy products provide adequate protection because most attacks are impersonal. That is, the attackers are not targeting you or your computer but are looking for any easy mark connected to the Internet. If you make it difficult for them to find and gain entry to your computer, they will most likely leave you alone. If a real hacker decides to attack your computer, you can make it difficult for him, but if he is good, he will likely find a way in. That is why large organizations have computer security staff and consultants working 24/7 to protect their computer networks. Unless a hacker has some reason to make a personal attack on your computer, you should not worry too much about a direct assault. The only way to make your computer completely hacker-proof is to turn it off or disconnect it from the Internet. The real issue is how to make your computer 99% hacker-proof. 

You do need protection because every time your computer is on, it is exposed to prying eyes and, in some cases, malicious hacker attacks. If you would like more proof, you can test the security of your computer. First, try Shields UP!. It’s an excellent website to test how secure your computer is, as well as a great place for information on firewalls. Then, you can try HackerWacker; both are good sites to test your computer’s security from possible attacks.

Table. Websites for Information on Personal Firewall Programs
Tool Publisher Website
BlackICE Defender Network ICE
McAfee Personal Firewall McAfee.com
Internet Connection Firewall Microsoft
Norton Personal Firewall Symantec
Sygate Personal Firewall Sygate Technologies
Freedom Personal Firewall ZeroKnowledge
Zone Alarm Zone Labs

FIREWALLS 
You can make your computer less vulnerable to attack by installing firewall software onto your machine. Firewalls are designed to protect computers from log-ins from the outside world, that is, the rest of cyberspace. A firewall will help prevent hackers from getting into your system, or, if it fails to do that, it may at least alert you to the presence of an intruder.


A firewall is a program or hardware device that filters the information coming through the Internet connection into your computer system. If an incoming packet of information is flagged by the filters, it is not allowed through. Simply put, a firewall is a system that prevents unauthorized access to or from a private network by examining the incoming packets and/or requests coming from (in this case) the Internet. Firewalls can be set up with software, hardware, or both, depending on how secure you want to be. 

A personal firewall should be inexpensive and easy to install and use, offer clearly explained configuration options, hide all ports to make your PC invisible to scans, protect your system from attacks, and ensure that nothing unauthorized enters or leaves your PC. A personal firewall is like a valve that lets you access the Internet, but prevents the Internet from accessing you. The firewall simply masks from the Internet all the information and activity that is on your side of the modem. Firewall software can also alert you if and when anyone tries to break through that wall to access your computer. A firewall is a barrier to keep destructive forces away from your property. In fact, that’s why it’s called a firewall. Its job is similar to a physical firewall that keeps a fire from spreading from one area to the next. 

Firewalls use one or more of three methods to control traffic flowing in and out of the network: 

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(1) Packet filtering–Packets (small chunks of data) are analyzed against a set of filters. Packets that make it through the filters are sent to the requesting system, and all others are discarded. 

(2) Proxy service–Information from the Internet is retrieved by the firewall and then sent to the requesting system, and vice versa. 

(3) Stateful inspection–A newer method that doesn’t examine the contents of each packet, but instead compares certain key parts of the packet to a database of trusted information. Information traveling from inside the firewall to the outside is monitored for specific defining characteristics, then incoming information is compared to these characteristics. If the comparison yields a reasonable match, the information is allowed through. Otherwise it is discarded. 

Firewalls are customizable. This means that you can add or remove filters based on several conditions. Some of these are: 

  • IP addresses. Each machine on the Internet is assigned a unique address called an IP address. IP addresses are 32-bit numbers, normally expressed as four “octets” in a “dotted decimal number.” A typical IP address looks like this: 216.27.61.137. For example, if a certain IP address outside the company is reading too many files from a server, the firewall can block all traffic to or from that IP address. 

  • Domain names. Because it is hard to remember the string of numbers that comprises an IP address, and because IP addresses sometimes need to change, all servers on the Internet also have human-readable names, called domain names. A company might block all access to certain domain names, or allow access only to specific domain names. 

  • Protocols. The protocol is the predefined way that someone who wants to use a service talks with that service. The “someone” could be a person, but more often it is a computer program like a Web browser. Protocols are often text and simply describe how the client and server will have their conversation. 

  • Specific words and phrases. This can be anything. The firewall will search through each packet of information for an exact match of the text listed in the filter. For example, you could instruct the firewall to block any packet with the word “X-rated” in it. The key here is that it has to be an exact match. The “X-rated” filter would not catch “X rated” (no hyphen). But you can include as many words, phrases, and variations of them as you need.

Many of the most popular firewall programs are free, with paid upgrades to higher levels of protection if you are running a network. Most home and office users will get adequate protection from the free versions of firewall programs, but if you desire more protection, the upgrades are very reasonable in price.

CONCLUSION
I have been using a firewall for a few years. It is incredible the number of times in a day that the firewall protection is activated. Numerous attempts are made by a variety of programs and websites to access your computer every minute via the Internet. Keep your personal information and data safe from outside influences by using a firewall. It is just another type of insurance to have to protect your beloved computer.

Dr. Malcmacher maintains a general and cosmetic private practice in Cleveland, Ohio. He is a researcher and consultant with Dentique, Inc, a dental product and management consulting firm. Dr. Malcmacher is a frequent contributor to the dental literature, an evaluator for Clinical Research Associates, a visiting lecturer at New York University School of Dentistry, and has served as a spokesperson for the Academy of General Dentistry. He is a consultant to the Council on Dental Practice of the American Dental Association. He can be contacted at (440) 892-1810 or dryowza@iname.com.