A firewall is a security system that protects a computer, server or network against unauthorised access. Its role is to control the flow of data between your IT systems, or between your IT environment and the outside world, allowing legitimate connections while blocking those that may pose a risk.
A firewall can be compared to the security team at a building. Everyone who wants to enter or leave is checked. If they are authorised, they are allowed through. If not, access is denied. A firewall applies the same principle to the data travelling across a network.
In practical terms, a firewall continuously analyses network traffic based on predefined security rules. It can prevent a cybercriminal from accessing a server, block intrusion attempts, restrict communications with malicious websites or stop malware from sending information outside the organisation.
Some firewalls are installed directly on computers or servers to protect each device individually. Others are deployed at company network level to filter all communications between the Internet and internal systems, or between internal systems themselves.
The most advanced firewalls, known as Next-Generation Firewalls (NGFWs), can analyse the content of communications, detect sophisticated threats and automatically block certain types of cyberattack.
Strengthen my cybersecurity with MCG
Although a firewall is an essential part of cybersecurity, it cannot protect a business on its own. It must be combined with other security measures, such as regular updates, backups, endpoint protection, continuous system monitoring and employee awareness.
By filtering communications and preventing unauthorised access, a firewall acts as one of the first lines of defence against cyberattacks and helps protect a company’s data and operations.