Air-gapping is the physical separation of a system from external networks, especially the internet and other untrusted links. A truly air-gapped machine has no direct remote path for attackers to reach it, which can greatly reduce exposure to phishing, remote exploitation, malware delivery, and command-and-control traffic.
In cyber security, air-gapping matters most for high-value or safety-critical systems such as industrial controls, research networks, and backup repositories. Defenders use it to limit the blast radius of an intrusion and to keep essential operations available when normal connectivity is unsafe. In practice, air-gaps can be weakened by removable media, maintenance laptops, wireless adapters, or poorly controlled bridging connections, so security teams still need strict access procedures, asset inventories, and tested offline recovery plans. Attackers often try to bypass the gap by compromising insiders, supply-chain devices, or update processes that move data across the boundary.