Test Your Network With PingComments Off

Ping is a great utility to use to test if a server is up or if a server is responding in the correct time, but what if you could use ping to actually test your network infrastructure. Lets call it a “poor mans test”.

Linux ping allows you to specify the number of bytes that are sent to the server your pinging.

ping -s  127.0.0.1

The maximum packet size it 65507, this is 63.9990234 kilobytes, not a very big packet at all, but what if you sent hundreds of them a second?

Enter ping flood.

ping -s 65507 -f 127.0.0.1

To quote the ping man page:

Flood ping. For every ECHO_REQUEST sent a period “.” is printed, while for ever ECHO_REPLY received a backspace is printed. This provides a rapid display of how many packets are being dropped. If interval is not given, it sets interval to zero and outputs packets as fast as they come back or one hundred times per second, whichever is more. Only the super-user may use this option with zero interval.

Here is an example of the output

ping 192.168.10.27 -s 65507 -f
PING 192.168.10.27 (192.168.10.27) 65507(65535) bytes of data.
.
--- 192.168.10.27 ping statistics ---
267 packets transmitted, 266 received, 0% packet loss, time 4321ms
rtt min/avg/max/mdev = 11.476/14.489/30.344/5.301 ms, pipe 3, ipg/ewma 16.245/11.551 ms

If I had lost a packet it should show a packet loss. As you can see, the server is sitting on the same switch as my desktop. It dropped 0 packets and had a rtt of 11.476 ms.

Not bad!