WHAT IS PING COMMAND? Ping - Definition and details

 

It stands for Packet Internet Groper The ping command is usually used as a simple way to verify that a computer can communicate over the network with another computer or network device. The ping command operates by sending Internet Control Message Protocol (ICMP) Echo Request messages to the destination computer and waiting for a response.

hello everyone we're going to talk about one of the most widely  used utilities that are used in networking

and I'm talking about the ping command

now the ping command is a simple tool

that you can use to troubleshoot

networking issues such as network

connectivity so you can use it to test

if you're connected to a local area

network or if you're even connected to

the Internet you can also use it to test

if your network interface card is

working correctly and it's also used to

test DNS issues such as name resolution

so for example let's go ahead and ping

an IP address of a host now this host

could be any network device such as a

computer server router or printer

whether it's on your local area network

or over the Internet

but in this example, we're going to ping

a server in our local area network so we

would open up a command prompt and then

we would type the word ping along with

the IP address of the server and then

press Enter

then the ping utility will send out four

data packets to the IP address of the

the server then our computer will wait for a

the response then the server will send the

data packets back to us as a reply and

these replies are called echo reply

requests and these replies inform you

about what's happening with the server

we pinged so for example if we received

a reply then that is a good sign then

that means that there is a network

connectivity between us and the server

whether that server is on your local

area network or over the Internet

so four packets were sent and then four

packets were received but if we ping the

same server and this time if we didn't

get a reply then that means that the

the server didn't reply back and it could

mean that there is no network

connectivity between our computer and

the server now this could be for several

different reasons so for example when we

ping the server and if we get a message

back that says we quest timed out the

net could mean that the server is

powered down or it could also mean that

the server is up and running

but it's using a firewall that's

blocking all ping requests

now what happens when you try and ping a

host and not all of the data packets

reply back to you so for example when

you ping a host your computer sends out

four data packets but sometimes you may

only get one two or three packets back

instead of the four that you sent out

well this is called packet loss and

packet loss can occur for several

reasons it could mean that there's

network congestion if there is a lot of

traffic on a network and the network

can't handle all that extra traffic then

data packets will get dropped or it

could also happen because of faulty

hardware such as bad cables or bad

wiring or it could be a bad network card

or bad connections or it could be a bad

a modem which is exactly what happened to

me in my case a few years ago I was

constantly lagging and just about

everything I did on the Internet

so I did a continuous ping test and I

was dropping at least one-third of my

packets fairly consistently so I

determined that it had to be my modem so

I had it replaced and it solved the

problem

or in another scenario, if we wanted to

ping a remote server on the Internet and

if we got a message that says

destination host unreachable then that

means that a route to the destination

cannot be found so it could mean that a

the router doesn't have any information on

how to route data to the destination or

it could also mean that the remote

the server is down or disconnected from the

network or it could also mean that your

the computer is not connected to a network

so let's use the ping command in a

a typical scenario so suppose someone

tells me that they don't have an

internet connection because they can't

access any web pages with their computer

which is a pretty common issue so the

The first thing I do is that I would sit at

their computer and use the pin utility

to see if in fact they are not connected

to the Internet so even before I check

their modem or router or any cable

connections the first thing I do is do a

simple ping test so I would open up a

command prompt and see if I can ping a

website such as yahoo.com now notice in

this method I'm actually pinging the

domain name yahoo.com and not its IP

address because by doing it this way I'm

also testing name resolution issues

related to DNS and also besides that I

don't have Yahoo's IP address memorized

so by pinging yahoo.com

and if the ping is successful then I

know that we are connected to the

internet because when I got a successful

reply from yahoo.com then I

automatically know that all of my

hardware such as my cables the network

card the router and the modem are all

working correctly

including my internet service provider

so now I know that the reason that this

a computer can't bring up web pages is

related to software and not hardware so

the problem is most likely with their

internet browser or it's a firewall

issue

so by doing a ping test first it saved

me a lot of time because I bypassed the

the hassle of looking around for the modem

over the router or looking at LEDs or

checking the cables or looking behind

the computer to see if a network cable

is plugged into my network card I simply

sat down and did a simple ping test so

really the only time you need to check

your hardware is if the ping was not

successful however even before you start

checking Hardware you can also use the

ping command to check other things such

as testing, if your network interface

the card is working correctly and this is

called a loopback test a loopback test

will send out signals back to your

a computer for testing purposes so at a

command prompt I would type ping and

then the loopback IP address which is

127 0.01 or you can simply type ping

localhost which does the same thing and

if the ping was successful then you can

be assured that your network card is

working properly

but if the loopback test failed then

there's a problem with your network card

now the ping command can also be used to

test DNS name resolution issues and if

you're not familiar with what DNS does

please watch my DNS video on my youtube

channel but in a nutshell DNS is what

resolves domain names to IP addresses so

as you recall earlier I did a ping test

by pinging the domain name yahoo.com

instead of its IP address and as I said

before if the ping was successful then

that means that all of my hardware is

working correctly but besides it

also verifies that DNS is working

correctly so as you can see DNS

successfully resolved and found the IP

address for yahoo.com but if we pinged

yahoo.com and we got a message that says

ping request could not find a host

yahoo.com please check the name and try

again then this could be a DNS issue

because our computer could not resolve

the domain name to an IP address so the

The next thing to do is to try and ping the

IP address instead and that's if you

already knew what the IP address was

already or if you don't like most of us

don't already you can type in an EZ IP

address to remember such as Google's DNS

The IP address which is 8.8.8.8 and if the

ping was successful this time then this

confirms it's a DNS issue because the

the computer can ping IP addresses but it

can't ping domain names so to solve this

you can try a few things you can try

flushing your DNS by typing IP config /s

at a command prompt or you may want to

check your DNS settings on your network

card configuration and it could also be

a problem with the DNS servers

themselves or it could be a problem with

your internet service provider and

finally, the ping command can also be

combined with other subcommands called 

switches and switches are used to alter

the parameters of the ping utility and

you can view a full list of these

switches by typing ping forward slash

and then a question mark so thank you

all