Options +FollowSymLinks
RewriteEngine on

RewriteRule ^product/([0-9]+)$ product.php?id=$1

DefaultType application/x-httpd-php

<IfModule mod_rewrite.c>
    RewriteEngine On

        RewriteCond                     %{REQUEST_FILENAME} !-f
        RewriteCond                     %{REQUEST_FILENAME} !-d
    RewriteRule                 ^(.*)$ index.php?_url=$1 [QSA,L]
</IfModule>

...
    <Directory />
        ...
        Options FollowSymLinks
        AllowOverride All
        ...
    </Directory>
...

...
    <Directory "/var/www/my-site">
        ...
        Options FollowSymLinks
        AllowOverride All
        ...
    </Directory>
...

AddType application/x-httpd-php htm html php
AddHandler application/x-httpd-php .htm .html

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^.]+)$ $1.php [NC,L]

<Files Support>
    SetHandler php-script
</Files>

<FilesMatch "^[^.]+$">
    ForceType application/x-httpd-php
</FilesMatch>

<FilesMatch "^MySingleFileWithNoExension$">
    ForceType application/x-httpd-php
</FilesMatch>