Firewall

A firewall is a software or hardware based network security system. The firewall controls the incoming and outgoing network traffic of your computer. It analyzes the data packets and determines whether they should be allowed through or not, based on an applied rule set. A firewall establishes a barrier between a trusted, secure internal network and another network (like the Internet) that is not assumed to be secure and trusted. Many personal computer operating systems include software-based firewalls to protect against threats from the public Internet. Many routers that pass data between networks contain firewall components and, conversely, many firewalls can perform basic routing functions.

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