The request is not wrong, the server is wrong. Your answer makes sense though...I had a similar issue with Wordpress mangling redirects because it can't handle

The request is not wrong, the server is wrong. Your answer makes sense though...I had a similar issue with Wordpress mangling redirects because it can't handle absolute URI's after GET. When you change your internet settings on Windows to use a proxy, this is the format to which browsers generate requests. From RFC 2616 5.1.2 Request-URI http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html : 'To allow for transition to absoluteURIs in all requests in future versions of HTTP, all HTTP/1.1 servers MUST accept the absoluteURI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies.' My proxy shouldn't have to alter the request, according to the standard.