This policy setting specifies whether the UDP protocol will be used to access servers via Remote Desktop Protocol. If you enable this policy setting Remote Desktop Protocol traffic will only use the TCP protocol. If you disable or do not configure this policy setting Remote Desktop Protocol traffic will attempt to use both TCP and UDP protocols.
HKEY_LOCAL_MACHINE -> SOFTWARE -> Policies -> Microsoft -> Windows NT -> Terminal Services -> Client # fClientDisableUDP
Windows Components -> Remote Desktop Services -> Remote Desktop Connection Client