Novell LINUX ENTERPRISE DESKTOP 11 - ADMINISTRATION GUIDE 17-03-2009 Administration Manual page 276

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 19.10, "Output of the Command ping" (page 264), 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 19.10 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.
264 Administration Guide