What does an air gap in network security entail?

An air gap in network security refers to a significant security measure that involves the physical isolation of a network from any other network, particularly from the internet. This means that the network is not connected to any external systems or networks, which greatly reduces its vulnerability to cyber threats. By not having any physical or logical connections to other networks, the chance of unauthorized access, data breaches, or malware infiltration is minimized.

This method is often used in highly sensitive environments, such as military installations, critical infrastructure, and some types of financial services, where the data handled is particularly vulnerable or valuable. The primary advantage of an air gap is that it provides a robust defense against remote attacks, as any external intervention requires physical access to the isolated network.

The other options describe different concepts in network security that do not encompass the physical separative nature of an air gap, such as virtual segmentation, encryption methods, or cloud session management techniques. These different approaches can help secure a network but do not eliminate the risk associated with external connectivity in the same decisive manner as an air gap does.