When running on Windows with Kerberos, the usernames must have the Kerberos realm specified in all uppercase. If this is not done (e.g. I use Administrator@dgolub.10gen.cc instead of Administrator@DGOLUB.10GEN.CC as my username), the Mongo shell will fail to log on. I spent a decent amount of time trying to figure out why it wasn't working until I eventually found this documented on a third party web site at http://www.knowledgehunter.net/2014/11/mongodb-kerberos-and-windows/. We should really include this in the MongoDB documentation so that users don't have a similar experience.

CC: mark.benvenuto milkie craiggwilson