A communication method executed by a node in an ad hoc network having multiple nodes, includes receiving from a neighboring node of the node in the ad hoc network, a first packet that includes a sender address of the neighboring node and a first packet transmission count of packet transmissions from the neighboring node; extracting the first packet transmission count from the first packet; receiving from the neighboring node and after reception of the first packet, a second packet that includes the sender address of the neighboring node and a second packet transmission count of packet transmissions from the neighboring node; extracting the second packet transmission count from the second packet; determining whether the second packet is an invalid packet, based on the first packet transmission count and the second packet transmission count; and discarding the second packet upon determining the second packet to be an invalid packet.