Novell LINUX ENTERPRISE SERVER 11 - ADMINISTRATION Administration Manual page 265

For more information about using ip, enter ip help or see the ip(8) man page. The
help option is also available for all ip objects. If, for example, you want to read help
for ip addr, enter ip addr help. Find the ip manual in /usr/share/doc/
packages/iproute2/ip-cref.pdf.
Testing a Connection with ping
The ping command is the standard tool for testing whether a TCP/IP connection works.
It uses the ICMP protocol to send a small data packet, ECHO_REQUEST datagram,
to the destination host, requesting an immediate reply. If this works, ping displays a
message to that effect, which indicates that the network link is basically functioning.
ping does more than test only the function of the connection between two computers:
it also provides some basic information about the quality of the connection. In Exam-
ple 17.10, "Output of the Command ping" (page 251), you can see an example of the
ping output. The second-to-last line contains information about number of transmitted
packets, packet loss, and total time of ping running.
As the destination, you can use a hostname or IP address, for example,
ping example.com or ping 192.168.3.100. The program sends packets until
you press Ctrl + C .
If you only need to check the functionality of the connection, you can limit the number
of the packets with the -c option. For example to limit ping to three packets, enter
ping -c 3 example.com.
Example 17.10 Output of the Command ping
ping -c 3 example.com
PING example.com (192.168.3.100) 56(84) bytes of data.
64 bytes from example.com (192.168.3.100): icmp_seq=1 ttl=49 time=188 ms
64 bytes from example.com (192.168.3.100): icmp_seq=2 ttl=49 time=184 ms
64 bytes from example.com (192.168.3.100): icmp_seq=3 ttl=49 time=183 ms
--- example.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2007ms
rtt min/avg/max/mdev = 183.417/185.447/188.259/2.052 ms
The default interval between two packets is one second. To change the interval, ping
provides option -i. For example to increase ping interval to ten seconds, enter ping -i
10 example.com.
Basic Networking 251