APN settings connect the device to the internet via mobile carrier’s cellular network.
These settings include IP addresses, gateways, and other technical details that enable the device to access the internet and send MMS.
In addition to identifying a PDN, an Access Point Name may also be used to define the type of service(s), (e.g. connection to a Wireless Application Protocol (WAP) server and access to Multimedia Messaging Service (MMS)) that is provided by the packet data network.
In 2023, an incident was discovered where choosing the advancedinternet APN from the ISP KPN drained the battery of smartphones significantly faster.
This APN was designed to give internet access without a firewall and public IP addresses.