Under which of the following circumstances would the command ping output the string (DUP!)?
A. When the ICMP packets are send to a broadcast address and multiple hosts respond.
B. When the host being sent ICMP packets is on a different network.
C. When the router responds to the ICMP packet in addition to the host receiving the ICMP packets.
D. When the host sending the ICMP packet is the same host as the one receiving the ICMP packets.
題解
DUP為「duplicate」(重覆)的縮寫。當ICMP封包被多個主機回應的時候就會顯示「duplicate」的相關訊息。