As I understand it, apache2 uses "/etc/apache2/apache2.conf" as its main config file rather than "httpd.conf". I further understand that this file looks to other files for "virtual web servers", so I also need to consider the file "/etc/apache2/sites-enabled/000-default" (which symlinks to "/etc/apache2/sites-available/default".
I finally realized that the way apache2 uses these "other files" is by including them in the main "apache2.conf" file via an "include" directive.
So I went back and looked in the main "
apache2.conf" file for includes, and found that it also includes *.conf files within the "/etc/apache2/mods-enabled" directory.
Within this directory I found a "dir.conf" file, which contains:
<IfModule mod_dir.c>
DirectoryIndex index.html index.cgi index.pl index.php index.xhtml
</IfModule>
Making the assumption that this line tells apache2 which files to load by default within a directory, I added "
index.shtml" to the end of this "DirectoryIndex" line. I then restarted apache2, and boom, the page now loads properly.