In one embodiment, a service receives a device registration request sent by an endpoint device, wherein the endpoint device executes an onboarding agent that causes the endpoint device to send the device registration request via a cellular connection to a private access point name (APN) associated with the service. The service verifies that a network address of the endpoint device from which the device registration request was sent is associated with an integrated circuit card identifier (ICCID) or international mobile equipment identity (IMEI) indicated by the device registration request. The service identifies a tenant identifier associated with the ICCID or IMEI. The service sends, based on the tenant identifier, a device registration response to the endpoint device via the private APN.