That is, don't use Cassini in your development environment if you aren't planning to use it in production. For example, my customer is running IIS on their server. Why shouldn't I do the same? With what I have seen with Cassini, there is no reason. Cassini is great, but there are noticeable differences between it and IIS. I am using a third party menu that performs poorly through Cassini, but works fine on IIS. Others have documented differences in behavior with Cassini. Scott Lilly describes a couple ......