Questions[rdp](server)

At our office, all of our Windows 7 Clients get this error message when we try and RDP to a remote Windows 2008 Server outside of the office:

Your system administrator does not allow the user of saved credentials to log on to the remote computer XXX because its identity is not fully verified. Please enter new credentials

A quick google search leads to some posts they all suggest I edit group policy, etc.

I'm under the impression, that the common fix for this, is to follow those instructions on every Windows 7 machine.

Is there any way that I can do something via the Active Directory which could update all Windows 7 clients in the office LAN?

Is there a way to send the Ctrl-Alt-Del command to an RDP session (Windows Server 2008 R2) inside another RDP session (also Windows Server 2008 R2) without the first session catching it?

Ctrl+Alt+End and Ctrl+Alt+Shift+End do not reach the 2nd level session.

Top-level environment is Windows 7 Enterprise.

Windows Server 2003 allows 2 non-console and one console remote desktop connections. Is there a way to increase the number of non-console sessions allowed?

Is there a way to use rdesktop or another Linux client to connect to a server that requires Network Level Authentication?

From Windows Server 2008 R2 -- Control Panel -- System And Security -- System -- Allow Remote Access there is an option that says "Allow connections only from computers running Remote Desktop with Network Level Authentication". So with this enabled I can con not connect from Linux. I can connect from XP but you need SP3 and I had to edit a couple of things in the registry for it to work.

What port(s) should I open/NAT to allow me to use Remote Desktop?