Putting the Con (COM1, LPT1, NUL, etc.) Back in your URLs

One annoyance that some developers have run into with ASP.NET MVC is that certain reserved filenames are not allowed in URLs. The specifics of this restriction are accounted for in an interesting blog post entitled Zombie Operating Systems and ASP.NET MVC . This actually wasn't a restriction on ASP.NET MVC but was built into the core of ASP.NET itself. Fortunately, ASP.NET 4 fixes this issue with a new setting. In web.config, simply add <httpRuntime relaxedUrlToFileSystemMapping="true"/> to the system.web node. Here's a snippet from my web.config. < configuration > < system.web > < httpRuntime relaxedUrlToFileSystemMapping ="true" /> <!-- ... your other settings ... --> </ system.web >...(read more) ...