Abstract: A data packet transmission method performed by a gateway node includes determining a first Internet protocol (IP) address from an IP address pool according to a request data packet transmitted by a client. The IP address pool includes one or more reserved IP addresses not recognizable by a business server. The method further includes generating a first data packet according to the request data packet and the first IP address as a source IP address of the first data packet, performing tunnel encapsulation on the first data packet to obtain a second data packet that includes content of the first data packet, and transmitting the second data packet to the business server.