Embodiments of the present invention provide a method, a switch, and a system for processing a message, which relate to the field of communications technologies, and are used to improve real-time performance in ARP request processing when APR request flooding occurs. An access switch generates a mapping table in a communication process between an intra-group server and a DHCP server, where the mapping table includes mapping between the intra-group server and address information of the intra-group server; receives an ARP request sent by a source server, where the ARP request is used to indicate a destination server that the source server needs to access; searches the mapping table according to the ARP request, and when the address information of the destination server is obtained according to the mapping table, sends the address information of the destination server to the source server.