Why isn’t IIS logging the 400, or What is responding with 400

400iis-6loggingwindows-server-2003

I have a web application which makes a localhost webservice call to itself and is getting a 400 Bad Request back. The problem is that I'm having trouble tracking down the cause of the 400 since I can't attach wireshark or anything, and what's even more odd is that it's not logged in IIS logs.

On another machine I ran through the same scenario, but where the service is working properly, and can see the request successfully logged in IIS logs. The problem machine is logging every other request, so there's something fishy going on.

Is it possible that IIS would not log a 400 Bad Request for some reason?
If IIS isn't responding, where's the 400 coming from? Could it be some kind of firewall or something?

I'm not able to remote debug, but might be able to attach WinDbg if it would help somehow.

Best Answer

I was looking in the wrong place. For Errors, you need to look in systemroot\System32\LogFiles\HTTPERR.

http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/bcabdcfb-2421-4eab-b5fb-777c791daaa9.mspx?mfr=true