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A personal firewall is an application which controls network traffic to and from a computer, permitting or denying communications based on a security policy.

A personal firewall differs from a conventional firewall in terms of scale. Personal firewalls are typically designed for use by end-users. As a result, a personal firewall will usually protect only the computer on which it is installed.

Many personal firewalls are able to control network traffic by prompting the user each time a connection is attempted and adapting security policy accordingly. Personal firewalls may also provide some level of intrusion detection, allowing the software to terminate or block connectivity where it suspects an intrusion is being attempted.


Common Personal Firewall Features:

  • Alert the user about outgoing connection attempts
  • Allows the user to control which programs can and cannot access the local network and/or Internet
  • Hide the computer from port scans by not responding to unsolicited network traffic
  • Monitor applications that are listening for incoming connections
  • Monitor and regulate all incoming and outgoing Internet users
  • Prevent unwanted network traffic from locally installed applications
  • Provide the user with information about an application that makes a connection attempt
  • Provide information about the destination server with which an application is attempting to communicate


  • Instead of reducing the number of network-aware services, a personal firewall is an additional service that consumes system resources and can also be the target of an attack, as exemplified by the Witty worm.
  • If the system has been compromised by Malware, Spyware or similar software, these programs can also manipulate the firewall, because both are running on the same system. It may be possible to bypass or even completely shut down software firewalls in such a manner.
  • The high number of alerts generated by such applications can possibly desensitize users to alerts by warning the user of actions that may not be malicious (e.g. ICMP requests).
  • Software firewalls that interface with the operating system at the kernel mode level may potentially cause instability and/or introduce security flaws and other software bugs.

How to Choose a Firewall
Three basic types of firewalls are available for you to choose from:

  • Software firewalls
  • Hardware routers
  • Wireless routers

To determine which type of firewall is best for you, answer these questions and record your answers:

  1. How many computers will use the firewall?
  2. What operating system do you use? (This might be a version of Microsoft Windows, Apple Macintosh, or Linux.)

That’s it. You are now ready to think about what type of firewall you want to use. There are several options, each with its own pros and cons.

List of Different Firewalls:

Software firewalls

Software firewalls are a good choice for single computers, and they work well with several operation systems. (Windows Vista and Windows XP both have a built-in firewall too.)

Does not require additional hardware.Additional cost: Most software firewalls cost money.
Does not require additional computer wiring.Installation and configuration might be required to get started.
A good option for single computers.One copy is typically required for each computer.

Hardware routers

Hardware routers are a good choice for home networks that will connect to the Internet.

Hardware routers usually have at least four network ports to connect multiple computers together.Require wiring, which can clutter your desktop area.
Provide firewall protection for multiple computers. 

Wireless routers

If you have or plan to use a wireless network, you need a wireless router.

Wireless routers allow you to connect computers, portable computers, personal desk assistants, and printers without wiring.Wireless devices broadcast information using radio signals that can be intercepted by someone outside of your home (if they have the right equipment).
Wireless routers are excellent for connecting notebook computers to the Internet and networks.You might have to pay for extra equipment.
 Not all wireless routers come equipped with a built-in firewall, so you might have to purchase one separately.

Start using a firewall today

Connecting to the Internet can pose dangers to unwary computer users. Use a firewall to help reduce your risk.

Installing a firewall is just the first step toward safe surfing online. You can continue to improve your computer’s security by keeping your software up to date, using antivirus software, and using antispyware software. You can find a list of different firewall with their test result Here.