Imagine you are the information technology director of a medium sized company. You have two hundred employees and each of them have their own workstation. One guy may be watching a football game on his computer. Another one may be chatting online with an old friend. Another employee may be downloading music or a video. Another is having a video conference with a client. As the director of information technology it is your job to make sure that there is nothing illegal or illicit going on with all the computers in your company. Antivirus software is one option but that only defends against malicious code and it is limited to one way (incoming) communication. If you really were in this position, you would want something more substantial than just antivirus software that has to be installed on each individual computer. It is in these types of situations where being a networked company is a huge advantage. You already have the infrastructure to add what you need to have in order to maintain safety. That is firewall software.
A firewall is a security measure that is designed to block any unauthorized access or use of a network. Firewalls can work on both outgoing and incoming communications and typically includes antivirus software as part of its security program. Firewalls are particularly effective at securing networks instead of just one computer because a firewall can be added at the access point of the local network to the internet. So any user who tries to gain access to the network through the internet is given the same security treatment as a user trying to access the internet from the internal network. A firewall is fairly straight forward in its security methods. There are a few different ways that firewall programs go about determining if a certain communication is allowed or if it’s illicit.
One common way that firewalls are set up is by packet filtering. This involves a fairly significant investment of resources to keep it operable but it does provide supreme security. All information that is sent over local intranets or the broader internet is broken down into packets. Any packet that tries to go through the firewall software, either out from the network to the internet or vice versa is picked up and inspected to make sure it complies with all the defined rules of the company’s network. Most of this process can be automated but the advantage in this system lies in the fact that an actual human being can oversee the whole thing. This allows more focus to be put on increasing the overall security and efficiency of a network instead of pouring over the minutia of each packet that tries to gain access to the network.
The Computer Technology Training website has additional information that you might find useful.
