What is the difference between an antivirus and a firewall?
Short answer
An antivirus scans, detects, and removes malicious code from your device, while a firewall monitors and filters incoming and outgoing network traffic. Antivirus acts as internal inspection on your storage and running processes. A firewall acts as a barrier at the network perimeter, blocking unauthorized connections before data reaches your applications. Both work together to provide layered protection.
The details
An antivirus program inspects files, memory, and software executions for known malicious signatures or abnormal behavioral patterns. If a malicious file arrives via download or email attachment, the antivirus quarantines or deletes it before it harms the system. Modern endpoint security solutions also monitor system processes to halt actions like unauthorized file encryption or credential dumping.
A firewall operates at the network layer. It evaluates data packets against defined security rules, permitting safe traffic while rejecting unauthorized connections. Host-based firewalls protect individual computers from external probes on local networks, while hardware firewalls protect entire business or home networks. A firewall prevents an intruder from probing open ports, but it cannot inspect the payload inside an authorized download.
Because they defend different layers, you need both controls active. A firewall stops direct network intrusion attempts, but it will not stop malware you choose to download over an allowed web connection. Conversely, antivirus software handles infected files, but it does not block uninvited network scanning. Operating systems such as Windows and macOS include built-in versions of both tools by default.
What to do
- Verify that your operating system's built-in firewall is enabled for all network profiles.
- Keep your antivirus definitions and software updated automatically.
- Avoid disabling your firewall when troubleshooting connection issues unless testing temporarily.
- Ensure your home or office router has its hardware firewall turned on.
Terms explained
- Firewall
- A firewall controls network traffic between zones, such as the internet and an internal network, allowing or blocking connections according to rules.
- Malware
- Malware is any software designed to harm, spy on or gain unauthorized control of a device, network or account.
- Encryption
- Encryption transforms readable data into ciphertext that can only be turned back into readable form with the correct key.