While attending training I tried accessing the labs from my BYOD computer (Buy Your Own Device). I was warned before the training that the Global Knowledge labs were best working with an OS that supported Internet Explorer: "please use an Operating System that supports the Internet Explorer Browser. We have found that Mac Books do not work well when connecting to this environment".
I while back I was able to make the labs work from my personal Linux desktop, but it seems that the labs have been changed and my old method would not work anymore.
The solution was however quite simple. The Remote labs portal has information about accessing from a variety of devices. I've also got a document describing some NTLMv2 requirements. I used Firefox and logged in to the portal. When trying to connect I was offered to download an .rdp config file. I chose to save this file in the default location.
xfreerdp cpub-vcloud-launcher-RemoteApps-CmsRdsh.rdp /d:gklabs /u:username /p:password -nego