A firewall is a system or a group of systems that enforces an access control policy between two networks. In principle, the firewall can be thought of as 2 mechanisms; one which exists to block traffic, and the other which exists to allow traffic.

A firewall’s basic task is to regulate some of the flow of traffic between computer networks of different trust levels. Typical examples are the Internet which is a zone with no trust and an internal network which has a higher level of trust. The function of a firewall is to prevent intrusion on the private network.

Probably the most important thing about a firewall is that it implements an access control policy. If you don’t have a good idea of what kind of access you want to allow or deny, a firewall won’t help you. Firewalls alone are not a solution to the problem of securing a computer network. Users need to be informed and educated to see see security as a vital part of their computer use. Firewalls are important since they can provide a single point where security and audit can be imposed, this point is often known as a choke point. The choke point acts as a security gate allowing and denying access. This means that anytime you have a change the levels of trust the choke point can allow more are less access to your private network according to change in the levels of trust you defined in your firewall.

Types of Firewalls

Firewalls can be divided into 2 main categories; hardware and software;

1. Hardware firewalls block access to your computer/network using electronics to filter all incoming/outgoing traffic.
2. Software firewalls, are commonly included in Internet Security Software and filter inbound connection attempts using a database of known tricks hackers will use to gain access into your computer/network.

The further categories of firewalls are; Packet Layer. This analyses traffic on your network at your transport protocol layer. The Transport Layer is responsible for delivering data to the appropriate application process on the host computer. Circuit level. This validates that packets are either connection or data packets. Application layer. This ensures valid data at the application level before connecting. Proxy Server. This intercepts all messages entering or leaving the network.

The software section provides pratical advice on Software Features and functionality and includes articles such as….Windows 7 for laptops…Windows 7 Home….Anti virus software FAQ’s….Firewall buying guide….What is firewall software?….Benefits of Business Software?….Buying business software