A firewall is a network protection system that has been pre programmed with a set of rules that control traffic that comes in and out of the network. This security system can be hardware or software and it acts as a roadblock between a trusted network and one that is not trusted.
The firewall has a set policy to allow certain types of traffic while restricting any other type of traffic that is not defined in the policy.
Basically a firewall acts as a filter between your computer or a network of computers and the entire internet. You can choose what you will share with the internet and what will be restricted from coming in or going out.
Firewalls will use different methods to filter information and at times the methods can be combined. Depending on the layers of a network that the methods are used, you will have different levels of specifications of filtering options.
How firewalls work for personal computers
A firewall on a personal computer is not so complicated, it simply works to protect the PC from malicious software. Malware is the main threat to personal computers with viruses being the most common. There are also Trojan horses and spyware which can be transmitted to your PC through emails and popup messages.
A firewall can protect your PC by allowing all data to pass through except the one that shows a certain kind of characteristic associated with malicious software.
Alternatively it can block all other data from going through except a particular kind that has been predetermined.
Firewalls for businesses
For big businesses, the firewalls tend to be a bit complex since they are protecting large networks. The firewalls can be used to filter outbound data, for example certain emails or sharing sensitive data with any computer outside the network.
The firewall can also be used to prevent access to particular websites for example social media websites. The firewalls can also be used to prevent the outside computers from getting access to the business network.
When using a firewall, the company can choose to restrict all computers except one from sharing information.
The configurations of a firewall can be set up in different ways depending on the preference of the business and the particular need for protection. How they work will depend on the level of expertise of the IT specialists managing them.
Firewalls have also been designed to specifically protect web servers since they are the targets of attacks these days. Firewalls for servers tend to be more complicated because they are protecting vital information.