Professional Microsoft IIS 8

Configuring MIME Settings

MIME (Multipurpose Internet Mail Extensions) is an Internet standard that defines the content types delivered by IIS 8.0. Although originating with e-mail, MIME has carried over to be used by other communication protocols, including HTTP. HTTP uses MIME to establish which type of content is being requested by a browser. A browser requests not only content from a web server, but also information that specifies what the content type is. This information is returned from the server as a Content-Type field in the HTTP header. When the browser gets the Content-Type field, it can then determine how to handle the following content: Some content types (e.g., HTML pages or GIF/JPG/PNG images) are handled by the browser natively, whereas other content types, such as DOCX or PDF types, may need to be handed to a helper application. In the event that there is no configured helper application, users are usually prompted as to what they want to do with the unknown content.

In IIS 8.0, there is a master list of MIME types that are understood by the server. You can modify this list by adding, editing, or removing MIME types. In the case of IIS, MIME types are differentiated by file extension. If a file is requested that doesn't have a corresponding MIME type defined, a 404.3 error is returned to the browser. Additionally, a wildcard (*, application/octet-stream) MIME type can be added that will allow any file to be served, although this results in increasing the attack ...