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Firewalls Do(s) and Don't(s)

If you are using some form of Windows and are on the internet, then it is a good idea to have a firewall. There are many different ones available, free of charge, on the internet, SOME of which work better than the expensive ones you find in retail stores (I won't touch a computer that has BlackIce though). The 2 most common ones I see are ZoneAlarm and Sygate Personal Firewall. Most firewall programs monitor what applications/services are trying to access the internet and what is trying to access you. These programs will show you a warning message when they see something trying to get in or out and wait to be told what to do. This is VERY important that you pay attention to what it is asking and here's why:

Your firewall program shows you warning message similar to this: Internet Explorer is trying to access the internet!
Would you like to allow this?
(Yes) - (Always Yes) - (No) - (Always NO)

What do you do? If you ever expect to look at web pages again, then you don't want to block it from accessing the internet. Don't laugh.. I see it happen all the time.

Your firewall program shows you warning message similar to this: 66.69.167.11 is trying to access port 25 on your computer!
Would you like to allow this?
(Yes) - (Always Yes) - (No) - (Always NO)

What do you do? This is either someone getting into something they shouldn't be into or a virus on someone's machine trying to spread. Do NOT accept inbound connections, unless you know for SURE that they are trusted and they have a reason to access your machine.
You may even see something like this: Your firewall program has detected a DoS (Denial of Service) attack originating from 66.69.143.28!
Connections from 66.69.143.28 have been blocked for 5 minutes!

This is a warning message to notify you of a malicious attack attempt. If you don't know or trust the person at the IP address shown then you should report this act to abuse@domain-of-offender and include excerpts from your logs documenting the time that it happened and what was affected.
The most important things to keep in mind when using a firewall program are: If you're not sure what it is then BLOCK it.
Do NOT block ANYTHING permanently unless you're 100% sure that by blocking it for good you won't break anything.
If something doesn't work and it use to, then shutdown your firewall program and see if it starts working then. There may be a rule that's gotten messed up.

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This site is designed to be of some assistance, however is not meant to be your sole source of information. By following the suggestions given on this page you understand that you do these things at your own risk. The steps mentioned here may or may not work for your purposes. There is no warranty or support of any kind provided by HAL-PC for the topics discussed in this site. The only support for your home network that is given is by me personally, at my choosing, on my own time, and via email only.
I know... I hate disclaimers too.