Is your Moodle hosted on a server inside the entities network? or its it remotely hosted (outside entity)?
Does your school/entity have: a) a firewall b) an internal DNS server c) private IP scheme (10., 172., 192.)?
In order for a server behind a firewall to be accessed from outside that firewall, the firewall as to allow port 80 traffic. If firewall doesn't list the internal IP address of the Moodle server no one from the outside of your private network can communicate with it.
Moodle should use a fully qualified domain name ... ie, moodle.somenetwork.net to be accessible in a human friendly way ... ie by name. IF, in the internal DNS of your network, there is an entry for moodle.somenetwork.net then iPads/Tablets/Computers inside your private network can reach it by name. There is no entry in external DNS for the Moodle server.
'spirit of sharing', Ken