APN

APN stands for Access Point Name, a gateway between a mobile network and another data network, such as the Internet or a corporate network. It defines how a device connects to the external data services provided by a mobile operator and determines the routing path for data traffic.

In cellular networks, a device uses APN information stored on the SIM card or configured manually to establish a data session with the network’s Packet Data Network (PDN). The APN identifies the external network that the device should reach, and carriers may offer multiple APNs for different services, such as internet access, multimedia messaging (MMS), or enterprise VPNs. The network assigns appropriate IP addressing (IPv4 or IPv6) and may require authentication or specific security measures.

Configuration and management of APN settings are performed on the device or by the carrier. Typical parameters include the APN name, username and password (if required), MMSC URL, MMS proxy and port, and identifiers like the Mobile Country Code (MCC) and Mobile Network Code (MNC). APN type can specify default data, MMS, or other services, and protocols may include IPv4, IPv6, or both. Some devices support multiple APNs for different networks or roaming arrangements.

Common issues arise from incorrect APN settings or carrier restrictions, which can block data access or MMS. Troubleshooting steps include verifying the correct APN values with the carrier, ensuring the correct APN type, updating device carrier settings, and resetting network configurations.

APN use is most prominent in mobile broadband; the acronym can have other meanings in different contexts, but this article focuses on the Access Point Name as used by mobile networks.