After clean installing Windows Vista on my work computer, then installing Visual Studio 2005 and Visual Studio 2008, I suddenly faced problems with using dynamic ports when developing web applications in ASP.NET.
When web applications are executed in VS 2005/2008, they may run on dynamic ports on the development server, e.g. localhost:12345. This worked before my computer was clean installed. After installing, however, I found myself being redirected to www.localhost.com:12345.
After struggling with this for a while, I eventually found a solution here.
If you are facing the same problems as I did, I hope that this helps you out.