The present disclosure provides a method for communication between a network device and a terminal device, where the network device stores a correspondence between a link-layer address and an IP address that are of the terminal device, and the method includes: obtaining, by the network device, a first link-layer address; determining whether a quantity of IP addresses corresponding to the first link-layer address reaches a threshold; if the quantity reaches the threshold, selecting an IP address from the IP addresses, where a quantity of selected IP addresses is not greater than the maximum quantity; saving a correspondence between the first link-layer address and the selected IP address; and sending, according to the selected IP address, a message to a terminal device having the first link-layer address, where the message is used to notify the terminal device whether an IP address is selected by the network device.