In the directory where you plan to install Elgg, do the following:
Create the file .htaccess and add these two lines
RewriteEngine on
RewriteRule ^testing.php$ modrewrite.php
This tells the webserver to load modrewrite.php when testing.php is requested.
In order to get this test to work on some virtual servers, you may need to add:
RewriteBase /
prior to the RewriteRule line.
Create the file modrewrite.php with this line
<?php echo "mod_rewrite works"; ?>
Create the file testing.php with this line
<?php echo "mod_rewrite does not work"; ?>
Now use your web browser to load testing.php. The text that shows will
tell you whether mod_rewrite is working