This application provides a packet processing method, which helps resolve a problem that a network node between a user terminal and a DHCP server is relatively complex. In the method, a network node of an access network receives a first packet sent by a user terminal, where the first packet is used to request an Internet Protocol IP address from a Dynamic Host Configuration Protocol DHCP server and the network node obtains a second packet, where the second packet includes the first packet, information about a port, and a Media Access Control MAC address of the user terminal, the port is a port through which the network node receives the first packet, and the second packet is a packet except a DHCP packet. Additionally the network node sends the second packet to a controller.