ASP.NET MVC Routing vs. Reserved Filenames in Windows
This has been addressed in ASP.NET 4. http://haacked.com/archive/2010/04/29/allowing-reserved-filenames-in-URLs.aspx
You can apply a setting in web.config that relaxes this restriction.
<configuration> <system.web> <httpRuntime relaxedUrlToFileSystemMapping="true"/> <!-- ... your other settings ... --> </system.web></configuration>Hope that helps.
Since asking the question, I've found that the bug is in ASP.NET proper, not IIS or ASP.NET MVC, meaning that there's no way to work around it. The only solution is to manually forbid URLs matching these names and these names followed by a period and random characters.
For a similar reason, there can't be a web.config tag in StackOverflow.
http://stackoverflow.uservoice.com/pages/1722-general/suggestions/98871-web-config-tag-404-error