Virtual Server Administration Web Site CGI Error

I have been having a problem this morning. I have been trying to RDP into a remote computer from my machine. Through the RDP Session, I would open the browser and attempt to load the Virtual Server Administration Website on the remote machine (http://localhost/virtualserver/vswebapp.exe?view=1). When doing this, I would receive the following Error:

CGI Error
The specified CGI application misbehaved by not returning a complete set of HTTP headers. The headers it did not return are:

I noticed however that I COULD successfully hit the http://remotecomputername/virtualserver/vswebapp.exe?view=1 URL successfully if I hit it from the browser on my machine. So interesting problem, it worked from a remote browser, but not from the local browser in the Remote Desktop session.

After some I was having a hard time getting any meaningful search results on google or regarding the issue. After a little more digging (searched on “vswebapp.exe” “CGI Error”) . I got an interesting posting by David Wang of Microsoft in the forums. In his posting, David suggests:

“One of the causes of 502 that I can think of is if you RDP to the server and
then attempt to browse the admin website (with Integrated authentication
against a CGI like VSWebApp.exe) – there is a limitation in Windows Server
2003 which prevents that from working. “

The posting indicates that the problem has to do with trying to access the admin website through RDP. Interesting and It appears to be true.

As a work around, I found that if you launch the browser in the RDP session using RUNAS, you CAN hit the Admin website. Hmm. Not sure what the problem with RDP is when hitting the admin website, but it definitely appears to be the problem. In addition there are the following


  • Access the Virtual Server website from the physical console, not a remote desktop session.
  • Access the Virtual Server website from a browser on the remote machine
  • When RDP’d into the Virtual Server, launch IE with RUNAS (even with the same credentials) and Hit the Virtual Server website through the “runas”ed browser.