The default document extensions in order of rank are:
Please note that the above are listed in rank order. Therefore, if you
have both an index.htm page and a default.htm page in a directory, then
the index.htm will be shown as default because it is ranked higher.
Similarly, if you have an index.asp page and a default.aspx page, then
the index.asp page will be shown as default, because it is ranked
We recommend only having one of the above default documents in your directories.
The default document settings can be changed from your control panel.