Firewalls and Internet Sharing

Who Needs a Firewall? To that question I would answer "anybody who has a static IP address or an always-on connection to the Internet such as a DSL or cable modem. If you're a dialup user, your vulnerability is fairly low if you connect briefly and get off. You're at moderate risk if you leave a connection on for long periods at a time and/or have other computers networked to your dial-up computer.

What are the risks of an open Internet connection? The risks can include compromising confidential information, being harnessed to carry out attacks upon others, denial of service (port-flooding), and the introduction of viruses. You are also vulnerable to the misuse of the Internet by members of your family or organization.

What can a firewall NOT do? A firewall CANNOT substitute for good common sense in guarding against viruses spread by email. The only defense against this is to refuse to open ANY attachments that are executable (in the Windows world this would include EXE, COM, BAT and ZIP files) UNLESS you know and trust the source. This means also DO NOT OPEN THESE IF THEY ARE SENT BY "FRIENDS". You don't know whom they got it from!. You can always politely explain afterwards that you have a policy against opening executables. It is generally safe to open email attachments sent by authorized vendors.

What is my personal risk of having an Internet connection? Use the two tables below

Your Internet connection and usage
DSL or T-1 connection	4
2-way cable modem	4
1-way cable modem	3
Static dialup IP	2
Prolonged dialup use	1
Infrequent dialup use	0

Your Individual risk factors
Servers operated by you and accessible from the outside	+2
Internet connection shared	+2
Files and printers shared	+1
Sensitive or irreplaceable information	+1

To evaluate your personal risk, select your connection type from the left column and add ALL factors from the right that pertain to you. If the total score is 5 or more, you definitely need a firewalled connection. If your risks total 0 or 1, your risk is extremely low. If your score is 2 to 4, you need to evaluate your own individual vulnerability further, and err on the side of caution if you either operate a business on the connection, or the consequences of data loss or theft, or the need to reinstall your operating system would be catastrophic.

Is there anyone who should NOT use a firewall? Yes. If you are an Internet-gamer, this would mess things up. A firewall is designed to block any communication coming from outside that is not a reply to what you sent out. Also if you do ICQ chat this might not work any more, unless your firewalling software is set up for this. BUT you should still be concerned about your security. Your concern should make you take alternate steps to protect your security -- either 1.) use a different computer for work and for play, and be sure the two are NOT connected (this drops your risk score to 4 even with DSL) OR 2.) use Windows - 9x for your gaming and dual boot to another operating system whose files can be hidden from Windows-9x's view for your serious work. Examples of the serious operating system are Windows-NT, Windows-2000, linux, and OS/2. If you do this, for goodness sake don't destroy this security by mounting a file system driver to enable Windows-9x to access these partitions!

Despite these issues, Internet connection sharing remains a valuable way to save on costs. To determine what type of Internet connection sharing is best for you, first evaluate your personal risk as per the above tables and then Click on this link to continue