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What is a Firewall?
A firewall is a policeman or a security officer for the operating system. It restricts all “black-sheep" to enter from the doors. It is a barrier to keep ruinous forces away from our property. It is like a physical firewall that prevents fire from spreading out from one place to another. That is the reason it is called firewall.
Without a firewall, no computer is safe even if it the latest model in the market. A computer is exposed to all dangers when it is connected to the Internet. Though firewalls can't save you from all dangers, they still add a level of protection for your computer.
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What Can a Firewall Protect You Against?
A firewall protects your computer from many things but above all from hackers and malware. Hackers are people who are attempting to access your PC remotely, without your knowledge and consent. Why do they do it? Well, not only because they earn money from doing this but also because they want to steal private information, for fun or just to cause mayhem.
Hackers are known for sending malware to your PC. Malware includes pests such as viruses, Trojan horses, spyware, rootkits, etc. A firewall does not clean malware (an antimalware program does) but it can stop it from entering your PC based on rules you set.
Malware often comes integrated with an e-mail attachment and with catchy names like ‘free_games_download.exe’. When the attachment is opened, you install the malware on your PC. Some download websites have infected games, screensavers, utility programs, etc to download. Their purpose is to bring malware to your PC with means of the program you may download.
The risks of getting malware from within an internal network can not be neglected. Employees and other members within one particular network may have one or more hackers sitting among them. We would not want our files stolen or privacy exposed to anyone – whether from within or outside the network.
A firewall comes in use here as well, keeping an eye on all members of the internal network and preventing them from breaking into any PC with prying intentions. Moreover, a firewall would make sure users in the internal network use authorized resources that are located on the outside network.
Malware can bring havoc to the PC. Hackers can spy on you very easily with a malware-infected PC. A hacker can steal, delete, and change information on your PC. If you use Microsoft Outlook or another similar program, malware can read your entire address book and send itself to all your contacts in hope that others will open and run it, too.
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Place a Firewall, So That Your Computer Does Not Become a “Zombie"
Hackers use the computer's address ( called an Internet Protocol (IP) address) to reach your computer. Where do hackers get my computer's IP address from?
They have variety of ways for obtaining one’s IP address. We visit a website, which seems to be safe from hackers but it actually isn’t. The website logs your IP address and the hacker can then use it to reach you with threats. This mostly applies to PCs having a static IP address because it doesn’t get changed much often – giving good time to hackers to try to break into your PC.
We shouldn’t forget that hackers are very smart (at least some of them). They send threats to random IP addresses and try where they can break in. The presence of a firewall is easy to detect and a good hacker can gain remote access through a firewall but when there is no firewall at all, it is much easier for him or her to penetrate your computer.
A computer that has been infected by a virus is often called a 'Zombie'. It is because this PC now acts as a 'friend' of the hacker and plays an important role in infecting other computers, too. One of the most common problems 'Zombies' have been involved in is DoS (Denial of Service) attacks. Many a times the computer owner is unaware of the fact that his computer has become a 'zombie'.
Therefore, we need to make certain that there is no malware on our PC. Once you have a firewall, then it can be very much your say on what you want to let in and out from your computer since you can configure which ports on the firewall to block. If you have Windows XP or a newer version, it has a built-in firewall already doing the job rather effectively.
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The Built-in Windows Firewall vs a Third Party Firewall
Some experts tell us how important it is to have a 3rd party firewall. According to them, the Windows built-in firewall does not offer real protection.
A PC World article has quoted David Overton a Microsoft technical expert, saying that the Windows built-in firewall does not prevent malicious code to go out of a PC. He also said that Microsoft contends that companies should use 3rd party programs to monitor the outgoing traffic. He further added that if malware gets past the firewall, it is the responsibility of the antivirus program to handle it.
Can we use Windows Firewall in conjunction with a 3rd party firewall? The answer is no. Adding a second firewall on the same system might cause configuration conflicts and it slows down the performance, too.
For those who are interested in installing a 3rd party firewall program and for older versions of Windows that do not come with a built-in firewall, there are many firewall applications available to purchase and some are even free of cost. I would recommend ZoneAlarm, which is free, comes with friendly interface and offers maximum security.