A firewall is a system — hardware, software, or a combination — that controls network traffic between zones of differing trust levels, applying defined security policies. In the classic configuration, it sits between the corporate network (trusted) and the Internet (untrusted); in modern architectures, it can exist between internal segments to support zero-trust.
Firewalls have evolved significantly. The early generations (stateless packet filtering) checked only IP headers and ports. The following generations (stateful inspection) tracked the state of connections. Modern firewalls (NGFW, Next-Generation Firewall) inspect application content, identify applications regardless of ports, integrate with user identity, and block known threats in real time.
INFOS implements firewall architectures aligned with the best practices of Cisco (a partner since 2006) and other leading manufacturers. The most consequential technical decision is often not which product but how to segment the network — a well-positioned firewall in a poorly designed architecture is worth less than a modest firewall in a coherent one. Cybersecurity is an INFOS service that combines firewalls with EDR, segmentation, MFA and training.