A firewall is a tool which allows us to protect a computer. Firewalls monitor and block incoming and outgoing connections to a network. A firewall can be software that is installed on a computer, but for larger organisations can be a hardware appliance. To defend against hackers outside of the computer system the firewall can block their incoming connections. If the hacker is inside the system a firewall may prevent data leaving the network
OCR GCSE Computer Science · Identifying and preventing vulnerabilities
Edexcel GCSE Computer Science · Preventing Network Security Risks
Pearson BTEC Digital Information Technology · Data level protection