Introduction to APN

APN (access point name) is the settings a mobile phone uses to tell itself where and how to connect to a server.
Without these settings, a phone is not able to establish an internet connection. These settings are different for every carrier and country.
However a lack of correct apn does not prevent a device from making telephone or text message connections as the settings required for these are always included with the sim card.
The settings include details such as ip address, port number, and apn type.