IIS: How to serve a file without extension?

Solution 1:

Assuming (path) is a physical directory on your machine, create a new web.config file in that directory with the following content:

<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
     <system.webServer>
         <staticContent>
             <mimeMap fileExtension="." mimeType="text/xml" />
         </staticContent>
     </system.webServer>
 </configuration>

You are telling IIS that for this directory only, any file without an otherwise defined extension (in MIME types) should be considered an xml file. Other file types in the same path should still work.

If you have the Windows feature IIS Management Scripts and Tools installed, you can use PowerShell to create such a web.config file:

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST/Default Web Site/.well-known'  -filter "system.webServer/staticContent" -name "." -value @{fileExtension='.';mimeType='text/xml'}

in this example Default Web Site is the name of the web site and .well-known is a directory under that site.

Solution 2:

It can be done in IIS 6 as well / without using web.config, but instead using the management GUI to add a MIME type for extension . here:

For instance, to serve a .well-known/acme-challenge token, create a virtual directory called .well-known, and have it take its contents from a physical directory (that cannot have names with leading dots in windows). Then add a text/plain MIME type for the extension . in this directory, and you can manually acquire new letsencrypt certificates for a domain that is currently served by an old IIS.