E:/>ping 172.1111
Pinging 172.0.4.87 with 32 bytes of data:
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Ping statistics for 172.0.4.87:
Packets: Sent = 4, Received = 0, Lost = 4 (100%
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
怎么会是这样呢?网络学的不扎实,哪位给小弟讲解一下