A tűzfal, or firewall, is a security system designed to monitor and control incoming and outgoing network traffic. It acts as a barrier between a trusted internal network and untrusted external networks, such as the Internet. By filtering data packets, a tűzfal helps protect computers and networks from unauthorized access and cyber threats. There are two main types of tűzfal: hardware and software. A hardware tűzfal is a physical device that sits between a network and its connection to the Internet, while a software tűzfal is installed on individual computers. Both types work to ensure the safety and integrity of data within a network.