


First up the original Remote Desktop Connection (mstsc) on Windows:

Here are the client certificate warnings on various Microsoft Remote Desktop clients, including OS X. Client Warnings for Untrusted Certificates While I may only be configuring certificates in my lab environment, there’s not much effort required to remove these certificate warnings. To get OS X clients to accept the certificate takes a little extra configuration not required on Windows clients. An environment with an enterprise certificate authority can enable certificate autoenrollment to enable trusted certificates on the RDP listener, thus removing the prompt. When connecting to a Windows PC, unless certificates have been configured, the remote PC presents a self-signed certificate, which results in a warning prompt from the Remote Desktop client. Windows has supported TLS for server authentication with RDP going back to Windows Server 2003 SP1.
