Air gap

A network with no outbound internet connectivity. Common in bank core systems, defence, and critical infrastructure.

The consequence for software is sharp: anything that requires a call out — licence checks, telemetry, font downloads, an external API, auto-update — will not work. Not "work slowly", not "work with limitations". Not work.

What it means for patching

The update bundle itself arrives through a controlled transfer, so the schedule depends on transfer cadence as well as on window availability. That is another argument for planning windows in advance: the delay getting content into the network adds to the delay in coordination, and the two compound.