#ping command

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Also see:

-> UNIX ping Command Examples

-> How To Add Jobs To cron Under Linux or UNIX

[serversuit-blog]

Ping It!

All the network and IT professionals need to be familiar with the ping command, so hopefully today’s article will teach you something new about it and its best practices.

The name PING actually comes from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects underwater, though sometimes it’s interpreted as a backronym to Packet InterNet Groper.

Ping is usually measured in milliseconds (ms), and It’s the main troubleshooting technique for an PING used to find out whether the host or gateway is reachable or not. It will also calculate the RTT (Round Trip Time) for the packet to reach its destination.

I am using UBUNTU 14.04.03 LTS Linux OS here to show you some ping examples, but this will work on any other Linux distro you have.

Check Ping Version

Open terminal and write the following command

ping -V

It will return the currently installed ping version on your system.

Simple Ping Test  

The ping command takes only one parameter: hostname or host IP address. To check this simply open terminal and type the following command

ping serversuit.com

To stop the ping you need to press CTRL+C in Linux. Without doing so, it will ping for indefinitely which can be useful if you’re trying to find the rate of packet loss and don’t know the average rate ahead of time.  After execution of every ping command, it will display a summary report with following outputs.

min: it will show minimum time taken to get a response from host that is pinged from your side.

avg: it will show average time taken to get a response from host that is pinged from your side.

max: it will show maximum time taken to get a response from host that is pinged from your side.

mdev: this is the moving standard deviation, sometimes also abbreviated "MSTD".

Also there is a TTL field which stands for Time to Live. It is also known as hop count.

Ping Counts

As in the previous example, using the ping command without passing any parameters will ping infinitely on Linux. Fortunately you can define the count limit for ping command. The command is as follows:

ping -c 6 serversuit.com

Change the Time interval of Ping Command

By default, ping waits for 1 second before sending the next packet towards the destination host. You can change this time by using parameter -i. If you, for example, want to change time from 1 second to 5 seconds, the command will look like this:

ping -i 5 serversuit.com

If you want to decrease the time interval, this is the command

ping -i 0.4 serversuit.com

Changing Packet Size

The ping command sends 64 bytes request to a host by default, where 56 bytes are data along with 8 bytes of ICMP header. If you want to change the sizes of packets then you can use this command like so

ping -s 200 -c 2 serversuit.com

Flood Test

Flooding is to test the network performance and send packets as soon as possible. Here’s the command

ping -f serversuit.com

To stop flooding, use the CTRL+C command as this flooding will also run indefinitely if it’s not stopped manually.

Summary Statistics

If you want, you can actually get a  summary statistics report without seeing the ping requests execution in terminal. This is the command:

ping -c 4 -q serversuit.com

Timeout Responses

To specify ping response while setting time limit you can use the -w parameter. This is the command:

ping -w 3 serversuit.com

As you can see, the ping command terminates after 3 packets like we specified.

Ping outputs Explanations

After pinging the host you will get different outputs from the ping requests These are:

“Request Time Out” - If you see “Request Time Out” it means there was no response from the host within the default timeout of 1 sec. This kind of result usually occurs due to causes such as network congestion, ARP request failure, routing error, cable fault, switch or router port problem, etc.

“Destination Host Unreachable” - If you got the “Destination Host Unreachable” message, that means there’s simply no path to the host, whether due to an incorrect address, or the host is offline altogether.

“Unknown Host” - If you will type wrong hostname, once the ping request is executed it will return the “Unknown Host” error.

That about does it for the ping command. Ping is a very simple tool, but it has a vast number of uses when it comes to troubleshooting network issues so it's pretty important to know about. If you have any questions about this article, or any other article we post for that matter, feel free to hit us up on @serversuit, comment on Facebook! Watch out for our articles released regularly! Until next time!

Technical How-To’s

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Use PING command to find a network problem

PING allows you to quickly verify the connectivity of your internet connection to the VPS server. It attempts to transmit a packet from your computer to a website on the network and listens for the response to ensure that it was correctly received. The most basic use of PING is simply the command PING and the destination IP address or host name.

For example, you can open a command-line window and use this command:

Start > Run > Type in cmd > Hit ENTER

In the Terminal window, you can type in commands like this:

ping 185.55.55.55

Or like this:

ping domain.com

This sort of PING command will most often result in one of two responses. You will either see something like this (which is a good response):

64 bytes from server.domain.com (185.55.55.55): icmp_seq=2 ttl=60 time=2.16 ms 64 bytes from server.domain.com (185.55.55.55): icmp_seq=3 ttl=60 time=2.23 ms 64 bytes from server.domain.com (185.55.55.55): icmp_seq=4 ttl=60 time=2.45 ms

Or you might see something like this (which is not a good response and indicates either your internet connection is having issues, or the server is not reachable):

Request timed out. Request timed out. Request timed out.

The reason you will see multiple results is that the PING command will generally attempt to “PING” the destination three times. For example, you might see this:

Request timed out. 64 bytes from 185.55.55.55 time = 250 ms Request timed out. Request timed out.

In this case, PING did not locate the destination in a reasonable amount of time on the first attempt, succeeded on the second attempt, and it then failed on the last two attempts. This should give you a basic understanding of the PING utility when troubleshooting a network problem.