When using NAnt, a typical objective is to automate the entire get/build/test/deploy/test-deployment process with a relatively clean deployment server. This ensures that configuration nuances aren't being "assumed to already be in place." Furthermore, by having your NAnt script perform as much configuration as possible, the build script acts as highly accurate and self-maintaining deployment documentation. One particular configuration nuance when setting up Castle MonoRail is to add the "*.rails" application extension mapping to IIS. This shows how to do it automatically via NAnt.