iis-7.5

We have a multi-tenant application with a Web server in the following environment: Windows 2008 R2 Datacenter IIS 7.5 ASP.NET 4.5 All traffic forced into HTTPS Forms authentication We have some convenience redirects in place in the site's Web.config file. For one of the redirects, the URL parameter value is being mangled occassionally (< 1%) on the request immediately following the 301 redirect . The rule is intended to redirect URLs such as https://www.myapp.com/some_client_id/notifications to https://www.myapp.com/lms/profile/notifications.aspx?cid=some_client_id Here is its definition:

I was trying to track down why my site was so painfully slow in IE9 when I pulled out Fiddler and realised that every request is being sent 3 times (twice I get 401.2 and then a success). I verified this happens on all browsers, its just that Chrome's speed was masking this (or it could be that this has nothing to do with my sites performance issues in IE). I've set up break points in my begin/end request handlers and the request comes in for say a css file. It is not authenticated and the response goes out with a 401.2, I doubled checked that I'm not setting the response status anywhere