To troubleshoot a network problem I would like to inquire the real network "speed" for a given network adapter, which can be seen when opening the "status" of a network connection under Windows:
However I want to inquire this over the command line or with a small, separate tool because I need to request this for multiple network connections and don't trust the user to fetch the information properly. The network card "Speed/Duplux" setting is always "Auto Negotiate", so I can't tell from that what "Speed" I will get.