Unity 5.4 UNET ID

I am working on a multiplayer networking app in Unity. I have gotten to the point where I can successfully run a host and a client on the same machine. However, I am having trouble connecting the client to a host across computers. I've encountered an answer here: http://answers.unity3d.com/questions/990419/how-to-use-unity-51-networking-on-multiple-compute.html#answer-1064955

However, the link provided in that answer is now broken, and I can't find any information about obtaining a UNET ID for a Unity 5.4 app. Does anybody have any experience with multiplayer networking in Unity 5.4?