If you are accessing your apache page externally, then it sounds like the domain name is correctly set up. You need to now point your apache server default to your moodle folder. (Check /etc/apache2/sites-available/default)
Then you also need to check your moodle config.php and make sure that it is reflecting the domain name that you set up and not the internal ip.
What exact url are you using internally? Just the domain name or with the /moodle?