An Introduction to Firewalls


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Firewalls are network security systems that protect your computer by screening out viruses, worms and hackers who attempt to gain entry through the Internet and harm it. Consider it a digital wall between your computer and any other network that is known or believed to be insecure, including the Internet. The wall creates barrier between the two, preventing any unauthorized access or malicious attack to your computer.

System Lock

All messages from both ends (your computer and the other network) are directed to the firewall and screened there. Only those messages that meet all the pre-specified security criteria are allowed to pass through the firewall. Remaining get blocked at the wall and are unable to reach the other side.

A firewall also extends the same security to an entire network and the several computers inside the network. Intranet or other private networks (and the computers within those networks) can be secured from external, untrusted or potentially harmful networks using a firewall.

Why are firewalls used?

Security, as discussed earlier, is the primary purpose of using firewalls. A firewall protects your computer against attack from other systems and networks by screening messages. It also conceals the different ports of your computer so as to hide them from the sight of attackers. It controls the number and type of programs that get to use your private computer network or the Internet. In addition, a firewall allows you remote access to a trusted private network through a range of secure logins and authentication services.

Firewalls can be hardware devices or software applications. Most operating systems have software firewalls built into them. In systems running with Windows 7 or 8, Windows XP SP2 or Windows Vista, the built-in firewalls are turned ‘on’ by default as well. For using a single computer at home, this will suffice.

However, if you have multiple computers connected to your home network, it is advisable to invest in a hardware firewall to protect all computers in the network. In addition, keep the in-built software firewall ‘on’ on individual computers within the network as well. This prevents the spread of virus from one infected computer to another. Similarly, for computers used in an office network, both software and hardware firewalls are suggested.

Considerations in purchasing firewalls

If you are making an enterprise purchase, your first consideration will be hardware or software. In-built software firewalls are good enough for home computers or small-office networks. However, in enterprise settings, additional software reinforcements need to made. Generally, hardware firewalls are stronger (more effective) than software firewalls. They are more expensive as well.

Other factors that need to be considered (for both hardware and software firewalls) include throughput, number of new connections and number of computers that can be connected to one firewall. The storage available in a hardware firewall also needs to be considered. Go through the resources below to make an informed decision.

Additional learning resources

While there are no bad connotations associated with the use of firewalls, use a combination of positive and negative keywords while searching for information is a good idea. Search for the benefits of firewalls, complications that may arise due to firewalls and the key differences between hardware and software firewalls. Remember to learn more about the different types of firewalls as well.

In addition, go through the following resources for more information:

An overview of firewalls by Webopedia

Details about how a firewall works by How Stuff Works

How to buy a firewall by Search Security

Key features to look for in a hardware firewall by Tech Republic

Android Firewall