First of all, sorry for my late reaction!
Gutmensch,
You could be right about the different treatment of RDP connections, since it's Wiki page states that RDP is a proprietary protocol. (see: en.wikipedia.org/wiki/Remote_Desktop_Protocol) Edit: I read on the RDesktop page "Microsoft has recently made RDP specifications openly available via the MSDN library." (rdesktop.org/#docs and msdn.microsoft.com/en-us/library/windows/desktop/aa383015(v=vs.85).aspx)
Regarding group policies, I'm not a network expert on this, but do you refer to the 'Local Computer Policy'? If so, do I need to check certain settings in the 'Computer Configuration' or the 'User Configuration' tab? But apart from this, when I'm able to login successfully as an admin, I see no reason that the current settings limit my admin rights, compared with a MS RD session.
Rich,
No, there is no conflict when both clients are connected. The same situation happens when MS RD is closed. My FreeRDP version is up to date.
Regarding Network Level Authentication, you're able to connect this way using a Linux client? The client requirements on technet.microsoft.com/en-us/library/cc732713.aspx state that you need MS RD 6 or higher on a Win XP or higher OS version, so please elaborate.
Yes, this stuff is also new to me, LOL
Thanks both of you for the help so far!
Jim