The name ``index.html'' is traditional for the default file in a directory. Every Web server program I know about except Microsoft Internet Information Server (IIS) uses it. MS IIS uses ``default.htm''. This is part of a strategy Microsoft calls ``embrace and extend.'' They do things just a little differently, to create work for people who use Microsoft Web authoring software but install their content on a standard server, or use standard authoring software and install content on an MS IIS host. The goal is to get you to complain to your hosting company about how their servers are ``incompatible.'' This is supposed to create demand for Microsoft's Web server software.

Here's how well that worked:

Netcraft survey

My web servers search for default files in the following order:

index.html
index.shtml
index.cgi
index.htm

The first one found is the one displayed. If none of them exist, you get the automatic file index or the ``forbidden'' error. I have intentionally left ``default.htm'' out of the list. If your content uses ``default.htm'', you're probably using Microsoft Front Page. You'll avoid a lot of problems if you switch from its ``design for MS IIS'' mode to its ``design for standard servers'' mode.