Web server directory index

A scheme where web server serves a default file on per-subdirectory basis has been supported as early as NCSA HTTPd 0.3beta (22 April 1993), which defaults to serve index.html file in the directory. This scheme has been then adopted by CERN HTTPd since at least 2.17beta (5 April 1994), whose default supports Welcome.html and welcome.html in addition to the NCSA-originated index.html. Later web servers typically support this default file scheme in one form or another; this is usually configurable, with index.html being one of the default file names. ==Implementation==

index page. In some cases, the home page of a website can be a menu of language options for large sites that use geotargeting. It is also possible to avoid this step, for example, by using content negotiation. In cases where no known index.* file exists within a given directory, the web server may be configured to provide an automatically generated listing of the files within the directory instead. With the Apache web server, for example, this behavior is provided by the mod_autoindex module and controlled by the Options +Indexes directive in the web server configuration files. These automated directory listings are sometimes a security risk because they enumerate sensitive files which may not be intended for public access, in a process known as a directory indexing attack. Such a security misconfiguration may also assist in other attacks, such as a path or directory traversal attack. ==Performances==

When accessing a directory, the various available index methods may also have a different impact on usage of OS resources (RAM, CPU time, etc.) and thus on web server performances. Proceeding from fastest to slowest method, here is the list: • using a static index file, e.g.: index.html, etc.; • using a web server feature usually named autoindex (when no index file exists) to let web server autogenerate directory listing by using its internal module; • using an interpreted file read by web server internal program interpreter, e.g.: index.php; • using a CGI executable and compiled program, e.g.: index.cgi. ==References==