Hi there - We have a website running on Windows Server 2008 SP1 that's started to refuse http 1.1 requests on 01/01/2010 00H00 GMT We picked it up because our load balancer marked both servers out of service (and off course the site went offline) at that time and would only bring them back in to service when the probe was changed to include an http 1.0 request (the 1.1 probe is still failing…) I can reproduce the error by doing the following locally on the server: From command prompt: telnet localhost 80 then: “HEAD /path/to/probe/probe.html HTTP/1.1” This will be the result: HTTP/1.1 400 Bad Request Content-Length: 334 Content-Type: text/html; charset=us-ascii Server: Microsoft-HTTPAPI/2.0 Date: Mon, 04 Jan 2010 06:37:29 GMT Connection: close Connection to host lost. But on the following command: “HEAD /path/to/probe/probe.html HTTP/1.0” the following is returned: HTTP/1.1 200 OK Content-Length: 9 Content-Type: text/html Last-Modified: Wed, 16 Sep 2009 08:18:30 GMT Accept-Ranges: bytes ETag: "1d693226f866cb3:8" Server: Microsoft-IIS/7.0 X-Powered-By: ASP.NET Date: Mon, 04 Jan 2010 06:38:03 GMT Connection: close Connection to host lost. What is strange is that both replies have “HTTP/1.1” in the header. We have 4 front end’s (2x Production and 2x UAT) and all of them have the same problem. Is there anyone out there who’s had the same problem? Does anyone know the cause / fix for this? Regards Lourens

Hi Lourens,There is a dedicated forum handle HTTP / web related issues, i would suggest you to post your query under Http://forums.iis.net engineers would be able to assist you better.