Understanding What Is a Firewall and How It Works

Many organisations as well as individuals have electronic devices that keep them connected to the internet. Many, if not most, have firewall software installed to keep the devices safe. The function of a firewall is to provide network security by filtering incoming and outgoing network traffic based on a set of user-defined rules.

What is a firewall?

The main purpose of a firewall is to allow the non-threatening traffic to be accessed by the device and filter out the dangerous traffic. A simple, relatable analogy to understand what a firewall is would be the postal service. Generally, the postman delivers letters based on the address on the envelope to ensure the post is received by the intended recipient, which would be the traditional firewall. Latest firewall features can be compared to the post being scanned for anything threatening before forwarding it to the intended recipient, like they did during the postal Anthrax scare. Thus, in this analogy, the user-defined rules are that the address on the letter is correct, and the contents are non-threatening.

How does a firewall work?

Firewalls typically filter all the data that enters your computer network. If there are any malicious codes, or attack attempts hidden in these data packets, it will flag these items and prevent them from reaching your device. The earliest firewalls simply used simple rules to determine what is a threat by appearances, but the technology has advanced so much that it is now possible to look inside data content to determine if it contains any threats. Basically, the firewall works as a gatekeeper to shield your device from malicious attacks.

Types of firewalls

There are two different types of firewall: software and hardware.

Hardware firewalls are built into connectivity devices such as routers, and they are able to protect all the devices that are connected to the network and are preferred by organisations with bigger networks. It is fairly low maintenance as they require minimal configuration in order to work effectively. Hardware firewalls inspect small packets of data, determine the source and destination of these data packets, and based on a pre-defined set of security rules, determine whether to allow the data packet to continue to its destination, or to drop it.

Software firewalls are the most popular option for most home and individual users. They are usually sold as stand-alone applications or as a part of a complete anti-virus software package. Besides monitoring inbound and outbound traffic, software firewalls also protect against malware such as trojan horses and worms. They usually run in the background of devices with a low imprint on the device’s functions and resources. The software firewall is dynamic, so the user needs to keep updating it in order to access all the latest protection features available against the latest network threats.

The Importance of firewalls

With more of an individual’s or an organisation’s details available online, firewalls play an important role in protecting sensitive information, besides keeping your device safe from the source. If malicious programs do not have access to your devices in the first place, hackers and phishers have no chance of accessing your sensitive data contained in your devices.

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