做实验的时候看到ping出来的结果不是我们熟知的!或者.号，而是其他的符号，到网上baidu了一下，找到了这些符号的含义如下：
!
Each exclamation point indicates receipt of a reply
.
Each period indicates the network server timed out while waiting for a reply
U
A destination unreachable error PDU was received
Q
Source quench (destination too busy)
M
Could not fragment
?
Unknown packet type
&
!
Each exclamation point indicates receipt of a reply
.
Each period indicates the network server timed out while waiting for a reply
U
A destination unreachable error PDU was received
Q
Source quench (destination too busy)
M
Could not fragment
?
Unknown packet type
&
Packet lifetime exceeded
本文转自loveme2351CTO博客，原文链接： http://blog.51cto.com/loveme23/28859，如需转载请自行联系原作者
