(UE4.15.2) Just to help anyone having trouble with this in the future. Best than asking the client to send the position is to actually use the position of the socket on the Server to prevent cheating. The thing is, Dedicated servers don’t render the meshes, so skeletal meshes do not update their sockets or bones while not being rendered by default on the server part.
But there is this magic flag that allows you to set the skeletal meshes to actually refresh bones on update even when they are not rendered, just click on your Skeletal mesh component and scroll down to:
And these are the options, the first one is the one that allows you to do calculations without rendering…
Cheers.