This lock allows one to lock ethernet cables into recessed ethernet sockets, typically found on PC's, as well as routers and switches etc. that normally have sockets flush with their outer casing. 
For printing, infil can be 30%, no supports needed, standard width printing head.

I've also made an improved model with better compatibility, easier removal and with a warning message on the side:  https://www.printables.com/model/1069792-ethernet-cable-lock-for-all-scenarios