Firewall Facts - What It Can Do To Protect Your Computer
December 1st, 2008

The whole point of a firewall is to completely isolate your computer from the Internet. Everything that passes in or out of your computer hits this wall to see if it can pass or needs to be blocked. The information that passes through a computer is made up of packets. Each packet is given from one machine to another in a network. So the connections computer savvy people talk about are merely the passing of packets of information to and from other computers. This is used to send or receive a packet of information no matter if one computer is two feet or in another country from the destination computer. Every Internet packet has to have an address and port to go to. It must also have the port and IP address that it is being sent from to be recognized by the other computer. It is the same as having a letter with the address it is going to and the address of who sent it.

Firewall software inspects these packets of information as they try to pass through. As the data arrives at your computer the firewall looks at it before any other program on your computer. If the packet looks suspicious it can deny entry to the rest of the computer so infection can be avoided. A port is only open when the first arriving packet tries to connect. If it is ignored or denied the port is now closed and nothing else can get into it. It is a great tool to have because it is very selective about what it will allow in and what it blocks. It can recognize IP addresses and know which ones are safe and which ones are not. What this means is when you are running on a specific port all information can only come through that port and no others. Even if you had a trojan that opened a listening port it would not be able to be detected do to the fact the its port could not be accessed. The firewall would block the signal.

Many people like to build secure tunnels through the Internet to pass information to and from with out being intercepted. This can be very easy to accomplish using a firewall. No unauthorized traffic will be able to get any access to the information sent in this tunnel. All you have to do is instruct the firewall to allow connections from specific ports only from a particular IP address to yours. This will allow only those two computers to see that open port. No other machine will be able to detect the open port at all. You don't have to worry about accidentally blocking the entire net from your computer. Your firewall knows the difference between browsing and unwanted connections. The firewall will allow you to keep communicating with a particular site and still reject other sites from connecting to you. It can distinguish between an existing connection and a new one.

You can also get an extra firewall made for application level filtering. This adds tremendous protection for your computer. Their job to permit and deny based on IP addresses. It doesn't read the packets of information but does have a dialogue with the incoming server to identify it. This firewall protects the port that houses all your secure information like passwords, usernames, and credit card information. It is password based and unlike a regular firewall that allows a password work cracker to keep working on it till it figures it out, this one only allows three tries. An intelligent application level firewall can watch port 139 where this information is housed and completely block any unknown computer from getting it. It will automatically black list the attacking IP address to prevent any future attempts from that IP address. The best way to access a good firewall is with an excellent anti-virus and/or anti-spyware program. Most anti-virus programs come with highly sophisticated firewalls that can do wonders in protecting your computer. There are plenty of companies that will sell you just a firewall without having to change anti-virus protection as well. A firewall, as simple as it may sound, can offer you a tremendous amount of safety when connected to the Internet

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