What is a Firewall?
Firewalls are a security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules. These rules are used to ensure that your computer network is protected from malicious attacks such as viruses and hackers.
A firewall can be a hardware or software device. The choice is largely determined by the specific needs of your business or organization.
Hardware-based firewalls are devices that attach to the edge of a computer network, such as a router or broadband modem. They are often used in combination with other computer security measures, including antivirus software.
Software-based firewalls run on the host device requiring protection and use some of its CPU resources to filter inbound and outbound traffic. They can also detect and identify different programs running on the same device, allowing administrators to control which ones are allowed to communicate with the rest of the network.
Generations of firewall technology
The first iterations of firewalls came in the late 1980s and were based on packet-filtering technologies developed by Mogul, Reid, and Vixie at Digital Equipment Corporation (DEC). These systems were not designed to block malicious traffic; they simply filtered the information entering and leaving the network.
Today’s firewalls, however, are more sophisticated than those developed in the past and include stateful inspection, intrusion prevention software and an IPS. This type of firewall is more efficient and provides higher throughput, while utilizing context to make its decisions.