Network Troubleshooting using PING, TRACERT, IPCONFIG, NSLOOKUP COMMANDS

Watch my complete Networking Tutorial Playlist: http://goo.gl/WXNhTr

Video walkthrough for using the Command Prompt to troubleshoot network connectivity using 4 KEY COMMANDS: PING, TRACERT, IPCONFIG, NSLOOKUP

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Closed Caption:

hello and welcome to sake tech so this
video is about a series of network
troubleshooting tools that you can use
in command prompt to troubleshoot your
network and get some information on your
network
so in this video we're going to go over
for commands the ipconfig command the NS
lookup command the ping command and the
trace
RT the trace route command
so let's start with IP config for now
ok so the first command that i want to
go over is the ipconfig command the
ipconfig command is a very common and
very useful tool
it displays the current information
about your network so it will give you
basic information such as your IP
address for the computer that your
station known it will give you the IP
address of your router will tell you
where your DNS services where your DHCP
servers are so let's type in the basic
ipconfig command to start and usually
your local area connection is called the
ethernet adapter local area connection
so this is the connection where you plug
in your network cable the rj45 network
cable connects to the to the jack behind
your computer and this is the
information pertaining to that
connection
any way you can get your IP address on
the screen which is 192 168 that 1.10
it's also called the ipv4 address you
can get your subnet mask right here and
you can get your default gateway address
here
the default gateway is
your router so now I know the IP address
for my router by looking at this screen
arm as you can see you don't get much
information about your local area
connection here
so what I'll do is I'll clear the screen
typing CLS to clear the screen and type
in ipconfig /all to get more in-depth
information about your local area
connection
+ Enter and let's go back up to the
ethernet adapter local area connection
this time as you can see there's much
more information present the IP address
is still here
the subnet mask is still here the router
address is still here but this time you
can also see where is your dhcp server
in my case as you can tell the IP
address is the same as the rocker
address that means that my dhcp server
is currently reciting on the router and
then your dns server my dns server is
also 192 168 that one that one
it's the same as my Roger address that
means my dns server is also on my Roger
so you can see how this tool is helpful
in troubleshooting and information
gathering information gathering is a
part of troubleshooting
so you know when it comes to networks
dns dhcp the default gateway the subnet
mask
these are all important keywords and you
can get the information about these guys
right here
so if you're trying to troubleshoot the
dns server you can before hand type in
the IP config command and find where the
dns server is so in my case it's in the
Roger
so I would go to the router settings to
tweak the dns server
ok so let's so let's move on to the next
command
and this is all I want you to know about
the ipconfig command to clear the screen
and let's get on
ok so one of the commands you'll be
using a lot for network troubleshooting
is the ping command in command allows
you to send a signal to another device
and if that device is active it will
send a response back to the center
now for those of you are interested in
the details how of of how this works
that the ping command is a subset of the
ICMP internet control message protocol
and it uses what is called an echo
request
so when you ping a device you send out
an echo request and if the device you
pink is active or online
you get an echo response so already you
can tell why this is a good command to
troubleshoot
so for example if your router is down
and you try to ping it and you get no
response
then you know that the router is what is
giving you problems
so let's say let's run this command a
couple times and see what kind of
results we get
so let us let us are paying my router
ping 1921 saved that one that one
press ENTER and let we will analyze the
to print out here that we got so what
happens is we send out for packets to
the destination and the destination
response back with the same four packets
so as you can see here one two three
four
so this is a reply from 192 168 1 and 1
that is my Roger we sent out 32 bytes of
data and we got back 32 bytes of data
and we got it back in less than one mile
the seconds down here you get a summary
so it says packets and four packets
received four packets lost 0 so that
means this is a stable connection and
then there's another some statistics
here that is not important
so this is how the ping command works it
sends out an echo request using data
packets of of miniscule size and then
you get a response and you know that the
other device is actually alive
so let us paint on google
www.google.com and see what happens
so we've got a similar print out let me
just bring this to the top and as you
can see this is the IP address of google
and that is where we got the response
from as usual we sent out 32 bytes of
data but as you can see because google
is far far far away and not in my
basement arm
it took twenty nine milliseconds to send
our two to get a response from google
and if you look down here again
statistics are packets were sent for
received four lost 0 so the connection
was stable
finally let's pick a device that doesn't
exist this is going to yield the same
kind of results if a device wasn't
actually working
so if your daughter was down and you
ping your watcher but are you are not
going to get a response from it
so let's say pain 192 168 . - 200
press Enter so we're paying right now
and the request was timed out because
that device does not exist as you can
see the ping command is retrying is
going to retry four times the first
packet didn't go through
second packed second packet then go
through the third packer and the four
pack it did not go through and
as you can see at the summary packet
sent for received 0 and lost for so it
was a hundred percent lost the signal
does not exist
so if you think the device you get no
response and you lose all the packets
that means the system you're trying to
reach is not connected to networks
having network problems and this brings
us to the end of the ping command
let's clear the screen and move on to
the next command
so the next command is the trace our tea
command
so what the trace RT command does is it
lets you see step by step
a route of packet takes to the
destination that you specify
so if you send a packet to google.com
before the packet actually reaches
google.com it goes through a couple of
routers to reach the destination so it
will go to your router damn google to
verizon or comcast router and from there
is going to go to all kinds of different
routers before it reaches google servers
so you can also use the term hops
instead of routers
so if it takes 10 Rogers to get to
google.com you can instead say it took
10 tops
so how do you do how to use this this
command for troubleshooting
let's actually run the command and see
what kind of results we get
so I'm going to run the trace RT command
i'm not going to trace google.com
ok
so as you can see we're getting a list
of each of the routers that we were
hitting as we are closing in on
google.com and up here will tell you
what you're tracing and we'll do the IP
address for our google
ok so the trace is complete let's see we
have one two three four five six seven
eight nine ten eleven we went through 11
hops 11 Rogers before we actually
reached google.com
now if you look up up top here the first
router that we actually hit was my own
router i can tell by the IP address
right here
192 168 . one . one and it's the
wireless broadband router down at home
the next one because I i have my service
through verizon was verizon router so it
clearly go step by step through all the
hops and then after eleven hops we were
at google.com
what what what is the significance of
this
let's say your home network was
perfectly fine but there was a problem
with the verizon routers you can run the
trace RT command and if i offended if
there's any problems here it will
actually tell you what the problem is it
could say things like request time down
Destiny's destination unreachable
or you could also say that in so 16
milliseconds it could be saying like
five thousand milliseconds just to give
an example and I don't think you'll ever
see that but so that if the request
times out that means the problem lies
with one of the routers that has to do
with the horizon and then you can call
the horizon and you can tell them hey
you guys are having a problem because I
know
my router works because I ran the trace
RT command
so this is the idea behind the trace
RT command as far as troubleshooting
goes ok so that brings us to the end of
this command
let's clear the screen and move on to
the final command
ok so the final command i want to talk
about is the NS lookup command
this command will fetch the dns records
for a given domain name or an IP address
remember the IP addresses and domain
names are stored in dns servers so the
NS lookup command lets you query the dns
records to gather information
so let's say I wanted to know the IP
address of google.com
I could simply type in NS lookup and and
type in google.com
press ENTER and what let's analyze this
up right out
so the the first two lines here show you
which dns server was used to get these
results
my dns server happens to reside on my
router as you can see 192 168 . one .
one is my Roger
so that is also my dns server and the
answer that we got was this all these IP
addresses here are Google's IP addresses
now Google is a huge website obviously
it's not going to have one single IP
address and obviously the IP addresses
will change from time to time but if you
type in any of these IP addresses in
your browser it will take you to
google.com
so this is the basic idea behind the NS
lookup command
ok so this brings us to the end of this
video and if you guys liked the video
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videos of this sort and thank you for
watching have a good day guys