This application provides a communication method, a gateway, and a management method and apparatus. A first data center is configured to provide non-public cloud services, and a second data center is configured to provide public cloud services. A gateway configured in the second data center is connected to a first subnet of the first data center, and is connected to a second subnet of the second data center. The first subnet and the second subnet have a same private network segment. The method includes: a layer 2 gateway receives a first address resolution protocol (ARP) request packet, which is used to request a MAC address of a second device in the second subnet, sent by a first device in the first subnet, and the gateway sends the first ARP reply packet, which carries a first MAC address of the gateway, to the first device.