What is a firewall?

In current rapid changing computer technology edge having a firewall installed in the computer servers or mainframe can be considered as one of the mandatory tools or system or program to be installed in the computer. A firewall is to safeguard against threats from the internet that may jeopardize the software or the operating system in the equipment.

How Does The Firewall Works?
In a simple language I would say that a firewall will monitor the information traffic (inflow and outflow) where it will allow the 'good data" into the computer systems and also protect the equipment from attack by malicious users or software such as viruses from any attack. In other words, a firewall establishes a barrier between a trusted secure internal network and another network (e.g.the internet) that is assumed not to be secure and trusted. Firewalls exist both as a software solution and as a hardware appliance.
Figure 1

Categories of Firewall
There are various types and definitions of the firewalls available in the market that can easily be purchased. Depending on the type of the preference,needs and budget, consumers can easily purchase the firewall for their use.However in my opinion, these types of firewall can be categories into 2 broad spectrum of firewall namely 'Hardware Firewalls' and 'Software Firewall'.

a) Hardware firewall
This category of firewall is mainly used for multiple computer that linked to a network. The firewall are built into network devices such as routers and it can protect every equipment that linked to the network. However, to set up this category of firewall requires some configuration to work effectively. This firewall usually applies the method of 'Pocket Filtering techniques' where it will monitor the header of each packet that enters or leaves the network before it decide to accepts or rejects the packet based on user-defined rules Packet filtering is fairly effective and transparent.

b) Software firewall
This category of firewall is commonly used for a single computer network or also known for home users. The device usually come as stand-alone applications or as part of a complete specification such as anti-virus protection software especially when consumers purchased the new generation operating systems personal computer. Apart from monitoring the inbound and outbound data traffic, the firewall also protect the computer against Trojan or Worm applications. (http://support.microsoft.com/kb/321050).

How do we determined which firewall can complement our needs?
In order to select the appropriate type of firewall, we must first determine the type of information that we want to protect and evaluate how severe the consequences could impact us if an attack hits. It helps us to determine the amount of money and time that we should spend on purchasing appropriate firewall. Researches by the expert highlighted that it is important for us to identfy the true costs of firewall taking into consideration of the 'hidden' costs which includes installation, setup, training, maintenance and regular updates (http://www.referenceforbusiness.com/small/Eq-Inc/Firewalls.html#ixzz3HdsSZpzM)

In addition, the expert also highlighted some useful tips for the consumers to consider before making the choice of purchasing the firewall.

Among the tips are as below :-
i. A firewall should not affect or slow down the consumer's internet connection too obviously.
ii. To explore reviews on the intended firewall from a computer magazines or on the World Wide Web .

Upon attaining the desired review information, consumers will have a better understanding on deciding the desired firewall. It is also important for the consumer to test the firewall once the installation is completed. Based on the research, many firewalls are breached by hackers due to faulty installation or configuration.There are some basic firewalls available for free and can easily be downloaded from the World Wide Web. However these free firewalls only offers some basic options and do not provide technical support services in the event consumer face problems.
(http://www.referenceforbusiness.com/small/Eq-Inc/Firewalls.html#ixzz3HsaSZpzM)

Benefits of using Firewall
According to Brain Hooper of Demand Media, a firewall monitors consumers connection and prevent authorised date from entering consumers computer from a network or the internet .

The benefits are :-

• Monitors Traffic - determine whether it contains potentially hazardous to the network's security and prevent it from entering the systems.
• Block Virus (Trojans) - It blocks these types of intruders from infecting the computer files. Trojans are dangerous because it silently transmit information from the computer to a web server.
• Stop Hackers - it keeps hackers out of your network and prevent them from compromising the computer for illicit activity such as spreading virusses.

(http://www.cisco1900router.com/tutorial-of-firewall-types-and-their-advantages-and-disadvantages.html)
(http://science.opposingviews.com/benefits-firewall-security-3806.html)

The Disadvantages of a Firewall
According to Shea Laverty of Demand Media (http://smallbusiness.chron.com/disadvantages-firewall-62932.html), a firewall should never be the only line of digital defence.

Among the disadvantages are :-

1. Affect Overall Performance of a Computer - firewall software is constantly running and use processor power and RAM memory to perform it's function .
2. An Attraction to Intruder to Break Through The Firewall - Proof of satisfaction being able to break through the firewalls

(http://smallbusiness.chron.com/disadvantages-firewall-62932.html)