Troubleshooting Commands
215
It is important to be able to decipher the symbols that are echoed to the
screen while a ping is taking place. By default and for user mode, five ICMP
echo messages are sent. Let's look at a few samples:
Router_A>ping 172.16.1.10
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 172.16.1.10, timeout is
2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max
= 1/2/4 ms
Router_A>
Router_A>ping 172.16.2.130
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 172.16.2.130, timeout
is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router_A>
It looks good so far, but what do the different characters mean? Table
4.14 defines them.
T A B L E 4 . 1 4
ping
Character Map
Character
Explanation
!
Received an echo-reply message
.
Time out
U / H
Destination unreachable
N
Network unreachable
P
Protocol unreachable
Q
Source Quench
M
Unable to fragment
A
Administratively denied
?
Unknown packet-type
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