Q. If there is no index.html or index.php, Apache displays all other files in a Directory. How do I force Apache web server not to display my directory / folder list?
A.This controlled by a module called mod_autoindex or mod_dir.
You can completely remove (or replace) automatic index generation as per your requirements. The IndexIgnore directive adds to the list of files to hide when listing a directory. File is a shell-style wildcard expression or full filename. Multiple IndexIgnore directives add to the list, rather than the replacing the list of ignored files. By default, the list contains . (the current directory). Open your httpd.conf or .htaccess file and append following directive to block auto indexing for all pdf and mp3 files:
IndexIgnore *.pdf *.mp3
To enforce or deny complete folder listing, use *:
Save and close the file. Restart httpd if httpd.conf was updated:
# service httpd restart
=> Apache mod_autoindex help pages.