Question : Cannot use Remote Desktop connection on Windows 2000 server

I have a customer that is having problems using remote desktop to connect to ONLY ONE of his Windows 2000 Servers. Every time they try to connect they receive the error screenshot I have attached. I had the customer try to telnet thru RDP port 3389 from another member server and it fails. The server CAN telnet itself if it uses the 127.0.0.1 address and can also use RDC connection on itself but it gets to the login screen and is unable to login.

Troubleshooting steps I have taken.
- Windows 2000 server has been rebooted several times.
- Terminal Services is running and has been restarted.
- Port is set to 3389 under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\WinStations\RDP-TCP\Portnumber (value set to d3d).
- The FDENYTSCONNECTION HKLM entry is set from 1 to 0 which allows that radio button to be selected on "Enable Remote Desktop on this computer" and I already added all admin accounts in "Select Remote Users I also added remote Desktop services to admin accounts in the ADUC.
- Have referenced the http://support.microsoft.com/kb/270588 registry setting and it looks good.
- The servers do not have a windows firewall enabled. The network does have an ISA 2004 server with a firewall policy enabled acting as a proxy.

I been struggling with this issue for almost a month and would greatly appreciate anyone that has any experience with remote desktop and windows 2000 to lend me some tips on troubleshooting tips. I have attached a screenshot of the error being experienced.

Answer : Cannot use Remote Desktop connection on Windows 2000 server

As it sounds like the Remote Desktop service is running on the system, I would first suspect that the ISA Server is blocking the incoming RDP connection from the Internet.  I would suggest performing a port scan with Nmap from the Internet against the system's public IP address to determine if Remote Desktop is actually available through the firewall or not.

Here's an EE article on using Nmap to perform a port scan:

http://www.experts-exchange.com/Security/Misc/Nmap-Performing-a-Basic-Scan.html

Hope this helps...

Mike