Cisco IOS in a Nutshell, 2nd Edition

Name

ping — command

Synopsis

ping
ping host

Description

The ping command sends a sequence of ICMP echo request packets to the specified host. It is one of the simplest and most commonly used troubleshooting tools. If you omit the host from the command line and are in privileged EXEC mode, the router prompts you for the rest of the information.

Ping prints a special character for each packet indicating whether the router received the corresponding echo reply. Table 17-15 shows what these special characters mean. Ping also summarizes the success rate and the round-trip times.

Table 17-15. Ping success codes

Character	Meaning
!	Ping successful
.	Timed out waiting for reply
?	Unknown packet
&	TTL of packet was exceeded
A	Access list denied packet
C	Network congestion
I	User interrupt (if you hit CTRL+^)
U	Destination unreachable

Example

Router# ping 10.10.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms