Firewall vs Antivirus: The Difference Explained

It is common to hear the terms firewall and antivirus being used interchangeably in the cybersecurity universe. However, even though firewalls and antivirus are both part of the cybersecurity measures used to protect computer systems and networks from malicious threats, they are very different in terms of deployment and how they work.

In general, a firewall is essentially designed to keep external threats from gaining unauthorized access to a network or computer system by monitoring and filtering data traffic, while an antivirus protects computers from malicious threats that are present in the system.

What is a Firewall?


A firewall can be defined as software and hardware that monitors and filters data packets entering or leaving a computer network or system. It establishes a secure internal network, protected from external networks. By assessing all of the data traffic, a firewall reduces the threat of malicious packets making it through to the protected network or computer system, from external networks – including the internet.

Firewalls assess and filter all of the data going in and out of the secured network according to a set of preprogrammed rules. These rules are used to determine whether a packet of data is allowed through the firewall or not.

Any packets that are seen as threats, as per the rules, are not allowed to go through. The rules and policies governing the operation of firewalls may vary depending on the requirements of each specific application. However, each firewall comes with default policies that specify the three actions that can be executed by the firewall; they include:

  1. Accept: Data packets falling under this action are allowed to pass through to the protected network or system.
  2. Reject: Any packet falling under this action is blocked and an error message is generated.
  3. Drop: Any packet falling under this action is instantly dropped.

Main Forms of Firewalls

Firewalls come in different forms, including:

Software Firewall

A software firewall is designed to protect a computer system or network, a software firewall is simply a software solution that can be installed on individual computers or as a virtual machine in a network. A software firewall can control the operation of specific applications on the system.

These firewalls can be used as a second line of defense against online threats. For example, a software firewall can check updated databases when ascertaining the legitimacy of applications trying to access the system/network from the internet.

Since they are more affordable and easier to install, software firewalls are a better fit for home users and small businesses. These firewalls also give users more control over their protection features and functionalities, due to their customizable nature.

Hardware (Appliance) Firewall

A hardware firewall can be defined as a physical device that is installed, at the edge of a network, or between a network and the internet with the aim of monitoring all data traffic passing through. Hardware firewalls are also referred to as perimeter firewalls because they are designed to secure an entire network.

These firewalls are normally deployed by large organizations because their set up requires a lot of resources – an entire IT department in some cases. However, once in place, the entire network can be monitored from a single point.

Cloud-based Firewall (Firewall-as-a-service)

As the name suggests, cloud based firewalls are normally developed using cloud based applications and hosted in the cloud. Necessitated by the introduction of cloud computing, these firewalls are used to protect cloud infrastructure, applications and platforms.

These firewalls monitor and filter the flow of data between various internal systems of an organization and external domains. Unlike the other firewalls described above, cloud-based firewalls monitor data traffic at various points, and not at a single point.

What Is an Antivirus?

An Antivirus is a software solution designed to look for, detect and remove malicious software, such as viruses, worms, Trojans and adware among others, present in the code or files flowing through network or computer systems. There are many ways through which malicious software can make it into your system, including through email attachments and flash drives. An antivirus provides protection against such threats – i.e. those easily missed by firewalls.

To provide real-time protection against virus attacks, most antivirus solutions normally run continuously in the background after installation.

How Does an Antivirus Work?

To protect computer systems against malicious software, an antivirus follows a simple three step process:

  1. Detection: Infected files and/or programs are first detected through real-time searches initiated by the antivirus.
  2. Identification: After detection, the identity of the threat – whether it is a Trojan, worm or virus – is determined, by checking it against a database of known types of malware.
  3. Prevention/Removal: Lastly, to prevent the threat from spreading to other files, the infected file/program is isolated, fixed or completely removed from the system.

Main Differences Between Firewall and Antivirus

  1. Form of Deployment: A firewall can be deployed in the form of software and also in the form of hardware. An antivirus can only be deployed as a software solution.
  2. Type/Level of Security Offered: Firewalls are designed to provide network level security by monitoring and filtering all network traffic. However, an antivirus offers file or application level security by looking for, detecting and removing malicious software that has made it into a computer system.
  3. Mode of Operation: Firewalls secure networks and systems by keeping threats out. They normally monitor and filter packets of data passing through, in line with a predetermined set of rules. An antivirus provides protection by searching for infected programs and files in the system, before then removing them.
  4. Nature of Threats: Firewalls can only deal with external threats to the network or system. On the other hand, an antivirus is cable of dealing with both internal and external threats. This software can be used to search for and remove internal threats in a computer system, as well as external ones, like those in flash drives.
  5. Possibility of Counter-Attacks: Counter-attacks, such as routing attacks and IP spoofing, can be used against a Firewall; because it deals with external threats. However, launching a counter attack against an antivirus is not possible as the threats are normally removed completely after detection.


While firewalls and antivirus protect networks and computer systems against malicious threats, they are both very different from each other. A firewall prevents malicious threats from reaching your computer, while an antivirus looks for, detects and removes malicious software present in the system.