I have a WinXP hyper-v virtual machine running on a Windows Server 2008 R2 somewhere in a datacenter. I do some remote development on this machine and I would like to do so using the complete screen estate of my desktop monitor.

I can do that using RDP.

But, for a while now, some of my virtual machines have been getting hammered by brute force RDP password guessing attacks that make them really slow to the point of becoming unusable. Note that I have already tried using programs like RdpGuard, but it fails to do its job on my VMs for some unknown reason that their customer support can't identify. So I have been thinking about disabling RDP (or blocking the RDP port) and using TeamViewer instead.

However, I can't figure out how to connect to the VM with TeamViewer with a full screen resolution of 1920x1200 (my desktop monitor resolution). It seems that TeamViewer can only use the resolutions offered by the graphics adapter of the VM (and on hyper-v that seems to be 1600x1200? Why oh why?).

  • Is it possible to install some other (3rd party?) virtual display driver that supports 1920x1200?
  • Is there a teamviewer setting that I am missing? If not, what is the reason that TeamViewer cannot do the same thing as the RDP client?

I am grateful for any hints. After all, all I want to do is some peaceful remote development sigh.

Related question: Hyper-V guest custom resolution

  • Simple solution would be to change the port rdp runs on. – Grant Dec 22 '13 at 3:34
  • I thought about it, but from what I have read I gather that it will just be a matter of time until that port is found, too. – Reto Höhener Dec 22 '13 at 11:50
  • You could put a hardware firewall in front of the machine, allowing only IPs from your ISP's ranges to connect. Or setup a VPN and only allow RDP through the VPN. – Grant Dec 22 '13 at 15:42

Hyper-V's display has a maximum limit of 1600x1200. There doesn't seem to be any way to overcome this limitation.

The reason RDP can use higher resolutions is that RDP acts like a completely separate display. It doesn't rely on the video card or drivers of the hardware. This allows for multiple sessions on a terminal server, and lets someone be at the actual console while another user is logged in through RDP (for server OS versions at least).

Teamviewer, and VNC, and other similar programs work on the actual display. They basically take a screenshot and send it to you (in reality they do more work than that, but that's the basic idea). Because of this, they are limited to whatever the actual hardware says it can do. You can't have separate Teamviewer sessions because they all share the console.

The problem is people trying to brute force RDP. There are a few things you can do to help here, in addition to the RDP guard you are already using.

  1. If possible, upgrade the virtual machine to Windows 7 so you can use Network Level Authentication. It uses far fewer system resources than the old login screen authentication.
  2. Change RDP to run on a non-standard port. It won't stop people who are actively trying to break into your system, but it WILL stop many automated scans from trying.
  3. Setup a firewall to block connections to RDP except from a few IP addresses/ranges legitimate connections come from.
  4. Don't allow RDP remotely, and setup a VPN server to allow you into the local network. You can then RDP in once connected to the VPN.
  5. Setup a Remote Desktop Gateway Server, which sends all traffic over HTTPS, and requires authentication before it will connect you to the destination server. This also allows you to remote desktop to multiple servers without requiring separate public IP addresses for them. Most importantly, it will take the burden of authenticating random connections away from the Windows XP machine.

Although the VPN and RD Gateway options require a bit of additional setup on the client side, they will almost certainly fix the problem, and give you a safer and more secure network.

  • Thank you for the background info and the suggestions. I think I will try the non-standard RDP port and at some point this machine will have to be upgraded to Win7, too. I don't want to limit the IP ranges, and points 4 and 5 sound like too much effort for me. Please forgive me for not accepting this answer (I did give you a vote, though), as I have still hopes that eventually someone will find a way to get 1920x1200 resolution via teamviewer. – Reto Höhener Dec 23 '13 at 13:26

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