Firewall

A firewall is a network security device or software that acts as a barrier between a private internal network and external networks, such as the internet, to protect against unauthorized access, data breaches, and cyber threats. They are the first line of defense to block malware. Firewalls can be viewed as gated borders where every data transaction between a private network and the internet is checked and either permitted or prohibited based on predefined security rules. A firewall can be hardware, software, software-as-a-service (SaaS), public or private cloud.