What is firewall?

BY: Kwami Ahiabenu

Online security is a complex venture since it is made up of a number of many moving parts such as people, processes, systems, hardware, software and knowledge.

However, it is critical in today’s highly connected society.

The idea of online security is to provide users at all levels with some safety when they operate in an online environment by ensuring that their system and data is protected from unauthorised modification.

Just by logging on to the Internet, a user is exposed to countless risks ranging from attempts to steal personal information, receiving a deluge of unwanted emails(spams) or the take-over of a users’ computer to launch cyber-attacks on other computers or network.

A firewall is designed as a first line of defence to provide security for users by preventing unauthorised access to a computer, networks, devices, or private network such as intranets.

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As a security system, firewall work by constantly monitoring and controlling all outgoing and incoming traffic using predetermined security parameters.

Firewall can be considered as a security post which controls access to a facility allowing only authorised persons in, and denying unauthorised persons access to entry.

Typically a firewall establishes a barrier between a trusted internal network and an untrusted external network, such as the Internet.

At the core of how firewall function is filtering data packets based on programmed data characteristics such as Internet Protocol (IP) of information sources, key words, domain names and applications that are receiving and sending data over a network.

There is a distinct difference between a firewall and an anti-virus and the two are not to be confused. Whereas a firewall acts as a barrier against unauthorised incoming and outgoing traffic, anti-viruses are software programs that work to prevent, detect and remove malware, viruses and worms, from a computer system, device or network.

Software or hardware firewall

A firewall can come in the form of a software (a series of computer instructions and other operating information), hardware (distinct physical devices usually) or both.

Hardware firewall are built into a router; a networking device that forwards data packets between computer networks and controls traffic on the Internet.

Most Internet providers will provide these routers in order to connect their subscribers to the Internet.

For broadband internet users, the broadband router provided by the Internet Service Provider will have a router fire wall, so when you connect to the internet you are given some level of protection through the fire wall on the said device.

On the other hand, a software firewall is a computer programme that filters incoming and outgoing information transmitted to you via the Internet or a private network.

The software firewall basically analyses all in-coming and out-going information through its filters, and any unauthorised traffic is not allowed to pass through the system.

A company can set a firewall rule in order to prevent confidential documents (for instance confidential materials, market intelligence or mails containing trade secrets) from being transmitted over their network.

In such instances when the firewall detects such a file it will prevent it from leaving the company’s network.

Firewalls use one or more of these five methods to control traffic flowing in and out of the network; Packet-filtering firewalls, Stateful inspection firewalls, Circuit-level gateways, Next-gen firewalls and Application-level gateways (a.k.a. proxy firewalls).

Two types of firewall

Most home and office users running on Microsoft operation systems such as Windows XP, Vista, seven, eight, and 10 have preinstalled firewall on their computers which are turned on by default.

Unlike the firewall settings in Windows, the built-in firewall for Mac OS X is not enabled by default, therefore, Mac users have to turn on the firewall manually on their computers if they want this protection.

Some experts claim, these preinstalled firewall cannot guarantee users with the needed security, since they do not have dedicated boundary firewall required for complex networking environment.

In this case they recommended that users acquire specialised firewall solutions from internet security vendors with a more robust protective buffer for their network.

Depending on your security requirements, users can turn to a number of “free” software firewall solutions, such as Comodo Firewall, TinyWall, ZoneAlarm Free Firewall, PeerBlock and AVS Firewall.

Also they can buy licensed firewall such as NETGEAR ProSafe Firewall, FortiClient, AWS WAF SonicWall,Cisco Firewall, Imperva Incapsula, FortiGate etc etc which are available on the market.

In conclusion, firewall do not provide total protection for users on a network, however, they play an important role in acting as the first line of defence.

It is recommended that users install, in conjunction with firewall, the latest anti-virus, anti-malware and Virtual Private Network (VPN) programmes which encrypts all internet traffic so as to increase the level of protection on their systems.

The writer is the Director of Innovations at Penplusbytes.org e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. WhatsApp : 0241995737