The present disclosure relates to a gateway device and a method therefor, a medium and an application product. The gateway device includes: a processor; and a memory coupled to the processor and stored with instructions that, when executed by the processor, cause the gateway device to perform the following operations: during connection of the gateway device to an external network via a mobile network: receiving, from a first networked device, a data packet to be forwarded to the second networked device via the gateway device; determining that the data packet has a data volume greater than a threshold data volume; and intercepting the data packet.