It sounds like you’re referring to a common practice among some (especially those using older versions like SketchUp 2017 or 2018) to block the software’s online activation and license verification by editing the Windows hosts file.

Block Sketchup Host File Access

It sounds like you’re referring to a common practice among some (especially those using older versions like SketchUp 2017 or 2018) to block the software’s online activation and license verification by editing the Windows hosts file.