As packets arrive, they are filtered by their type, source address, destination address, and port information contained in each packet.
当信息包到达时，根据每个信息包中包含的类型、源地址、目的地址和端口信息来过滤它们。
2
He most likely looked for a dead port on the hub and plugged his laptop in with a packet sniffer installed on it, which promiscuously picks up traffic on a network segment.