Apache server

Mod_rewrite must be enabled on your server

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
RewriteRule ^index.php/(.*)$ [L]

Nginx server

After follow this tutorial Install phpFox on nginx server, you just goto AdminCP -> Settings -> Short URLs, then click to button "Enable Short URLs".