Embodiments of this application disclose a packet processing method. The method in the embodiments of this application includes: receiving a first negotiation packet from a second network device based on a first interface of a first network device, where the first negotiation packet includes a first source media access control MAC address; determining whether the first source MAC address is the same as a first locked MAC address stored by the first network device, where the first locked MAC address is a MAC address of a network device that is determined by the first network device and that has established negotiation with the first network device; and when it is determined that the first source MAC address is different from the first locked MAC address stored by the first network device, skipping updating a link status of a first link based on the first negotiation packet.