Firewall protection how to?

What is a Firewall? A firewall is a tool that monitors communication to and from your computer. It sits between your computer and the rest of the network, and according to some criteria, it decides which communication to allow, and which communication to block.
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Firewall protection how to?What is a Firewall?A firewall is a tool that monitors communication to and from your computer. It sitsbetween your computer and the rest of the network, and according to some criteria,it decides which communication to allow, and which communication to block. Itmay also use some other criteria to decide about which communication orcommunication request to report to you (either by adding the information to a logfile that you may browse whenever you wish, or in an alert message on the screen),and what not to report.What Is It Good For?Identifying and blocking remote access Trojans. Perhaps the most common way tobreak into a home computer and gain control, is by using a remote access Trojan(RAT). (sometimes it is called backdoor Trojan or backdoor program. Manypeople simply call it a Trojan horse although the term Trojan horse is muchmore generic). A Trojan horse, is a program that claims to do something reallyinnocent, but in fact does something much less innocent. This goes to the days wherethe Greek soldiers succeeded to enter through the gates of Troy by building a bigwooden horse, and giving it as a present to the king of Troy. The soldiers allowedthe sculpture to enter through their gates, and then at night, when the soldiers werebusy guarding against an outside attack, many Greek soldiers who were hidinginside the horse went out and attacked Troy from the inside. This story, which mayor may not be true, is an example of something which looks like something innocentand is used for some less innocent purpose. The same thing happens in computers.You may sometimes get some program, via ICQ, or via Usenet, or via IRC, andbelieve this program to be something good, while in fact running it will dosomething less nice to your computer. Such programs are called Trojan horses. It isaccepted to say that the difference between a Trojan horse and a virus, is that avirus has the ability to self-replicate and to distribute itself, while a Trojan horselacks this ability. A special type of Trojan horses, is RATs (Remote Access Trojans,some say remote admin Trojans). These Trojans once executed in the victimscomputer, start to listen to incoming communication from a remote matchingprogram that the attacker uses. When they get instructions from the remoteprogram, they act accordingly, and thus let the user of the remote program toexecute commands on the victims computer. To name a few famous RATs, the mostcommon are Netbus, Back-Orifice, and SubSeven (which is also known asBackdoor-G). In order for the attacker to use this method, your computer must firstbe infected by a RAT.Prevention of infections by RATs is no different than prevention of infection byviruses. Antivirus programs can identify and remove most of the more commonRATs. Personal firewalls can identify and block remote communication efforts tothe more common RATs and by thus blocking the attacker, and identifying theRAT.Blocking/Identifying Other Types of Trojans and WQorms?There are many other types of Trojan horses which may try to communicate withthe outside from your computer. Whether they are e-mail worms trying todistribute themselves using their own SMTP engine, or they might be passwordstealers, or anything else. Many of them can be identified and blocked by a personalfirewall.Identifying/Blocking Spywares/Adbots?The term spyware is a slang which is not well defined. It is commonly usedmainly for various adware (and adware is a program that is supported bypresenting advertisements to the user), and that during their installation process,they install an independent program which we shall call adbot. The adbot runsindependently even if the hosting adware is not running, and it maintains theadvertisements, downloads them from the remote server, and provides informationto the remote server. The adbot is usually hidden. There are many companies thatoffer adbots, and advertisements services to adware. The information that theadbots deliver to their servers from the computer where the adbot is installed, ishow much time each advertisement is shown, which was the hosting adware, andwhether the user clicked on the advertisement. This is important so that theadvertisements server will be able to know how much money to get from each of theadvertised companies, and how much from it to deliver to each of the adwaremaintainers. Some of the adbots also collect other information in order to betterchoose the advertisements to the users. The term spyware is more generic, butmost of the spyware fall into this category. Many types of adbots can be identifiedand blocked by personal firewalls.Blocking Advertisements?Some of the better personal firewalls can be set to block communication withspecific sites. This can be used in order to prevent downloading of advertisements inweb pages, and thus to accelerate the download process of the web sites. This is not avery common use of a personal firewall, though.Preventing Communication to Tracking Sites?Some web pages contain references to tracking sites. e.g. instruct the web browser todownload a small picture (sometimes invisible) from tracking sites. Sometimes, thepictures are visible and provide some statistics about the site. Those tracking siteswill try to save a small text either as a small file in a special directory, or as a line ina special file (depending on what is your browser), and your browser will usuallyallow the saving site to read the text that it saved on your computer. This is calledweb cookies or sometimes simply cookies. Cookies allow a web site to keepinformation that it saved some time when you entered it, to be read whenever youenter the site again. This allow the web site to customize itself for you, and to keeptrack on everything that you did on that site. It does not have to keep thatinformation on your computer. All it has to save ...