File Requests to UNIX or Linux Server Return Wrong File or Error
If IIS must access files on a UNIX or Linux system, file name case sensitivity can be an issue unless Network File System (NFS) support is enabled in IIS.
UNIX and Linux both support mixed-case file names, and IIS fully supports requesting static files in a case-sensitive manner. An issue arises, however, when IIS makes a subsequent request for a file from its static file cache. Because all file names are converted to uppercase letters in the IIS cache, any request after the first request from the IIS static file cache might fail or return the wrong file.
To remedy this problem, disable the IIS static file cache so that all file requests are issued fresh, thereby retaining correct file name case. The static file cache can be disabled for individual virtual directories on Web sites, or globally for all sites.
IIS "fully supports" requesting static files in a case-sensitive manner, but caches them using only all uppercase filenames? That hardly sounds like case-sensitive static files are fully supported in any possible definition of fully or supported. It's like saying a serial killer is fully rehabilitated if he only murders you the second time you meet him.