configuring moodle server behind a pix515e firewall

my moodle Linux based-server is behind a cisco pix 515e firewall. after configuring everything, im able to access moodle on the intranet but can acess it on the internet from anywhere outside the intranet. on the website settings on the config.php file i put a 10.10.x.x.x address that can is supposed to be able to be interpreted by the NAT. SO i cant figure out where im going wrong.