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Free CCNA | EIGRP Troubleshooting – Day 51 | 200-125 | Cisco Training

Cisco Certified Network Associate day 51
welcome back everyone I’m Imran Rafai your trainer for this entire series
today we’re gonna look at EIGRP troubleshooting and what we’re gonna do
is we’re going to download a lab so I will give you a link you can go to our
website and download a troubleshooting lab and then we will do the
troubleshooting together before we go ahead don’t forget to click on that
subscribe button and the bell ICON to be notified when we add a new videos and
also please click on that thumbs up to make us very very happy if you want our
social media contact that’s on on the screen on the left you have our company
contacts on the right you have my personal contact and for people who want
my email address it is imran dot for Phi at NW kini dot
o-r-g so what are we gonna look at today today like I said we are still into 0.6
to 0.6 is configure verify and troubleshoot yah GRP so this time we
will be looking at the troubleshoot part of EIGRP now before we come here
what I would suggest is go to our website the link for the lab is going to
be on the description but click on shop then go to I mean you could do here you
could just say sort by a latest and the first one which is day 51 EIGRP
troubleshooting so at the moment this is the latest but let’s say after one month
two months three months you you come it may not be the latest one right but you
know EIGRP troubleshooting once you click on that you come to this link and
this link I will put on the description so you can click on the description and
download so click Add to Cart view cart and you can go ahead and proceed to
checkout so once that’s done you will have the download so let’s login now I
proceed to checkout and it’s asking me for all this information I can obviously
you not see this but you can put your information here click on place order
once place order is done obviously there’s an order number that gets
generated and all that but this says a lot of people send me emails asking
where is the download this is the download button download it’s here
download it’s a big blue button just click on that button and you can
download whatever you purchased right so once you do this click on that and let’s
open it you can double click and it will open pick the cisco packet tracer now
this is a this is going to be a lab and and this lab I I configured this lab and
I’m sure I introduced a lot of troubleshooting configuration so
basically I must have configured it from but I don’t remember because I did this
lab about three or four months ago and because of other things that came up I
couldn’t complete this video so I don’t know what troubleshooting I have
introduced in this lab so let’s let’s try to troubleshoot so the aim of this
lab is the three pcs pc-1 pc2 one PC three should be able to ping each other
so let’s go ahead and see if that’s happening at the moment so when I click
on PC one I can go to desktop command and what’s the IP address it’s ping the
IP address for PC twos t so when I click on when I try pinging it
doesn’t work let’s see if if it can ping 30 dot 30 which is pc 3 it cannot ping
pc3 as well the same thing should apply to the other so let’s try from PC to
ping 10 dot one dot ten dot then its destination host unreachable and
you know what is destination host aren’t reachable that means there is no routing
table entry let’s try thirty two thirty exactly the
same thing so let’s try pc3 now pc3 the same thing ping destination
host unreachable let us try ping t it is the
same destination host unreachable so we’ll find out why it is not working and
it ideally should be configured with ERG RP so that’s something we’ve been
looking at this is a troubleshooting lab so we have three offices so Bangalore
office Boston office and Paris of office and they’re connected to each other and
EIGRP is running so now let’s go to router one and let’s see what’s
happening so let me okay right so show IP yeah GRP first let’s see if europe is
configured on this so sure run I think here begin yeah i GRP so i pei GRP yes
there is IP i jarppi configured okay and let’s let’s try that in all three so we
have some understanding of EI JP has been configured so show run begin
yeah ARP and we see a job is configured let’s see here
sure run begin yeah ERP and ERP is configured right perfect
so eigrp is configured on all three but for some reason it is not creating let’s
also go check the show IP route so we see erp is advertising DS
ERP so it’s learnt some route through yeah yeah but I see that it is a summary
route here and not a zero so not a zero if you remember last time we we said
that if you do auto summarization what happens is the router would start
summarizing the whole thing depending on how summarization is configured it is
going to summarize so in this case it is summarized the whole block of
whereas a lot of networks a subnets on that it is not part of so to
prevent loops almost all the routing protocols introduce a concept called
null 0 alright to understand null 0 what we will do is we will show you an
example so let’s say there is a router router 1 and then there is a router
router 2 and there is the internet right now what we do is normally from route of
one we let’s say have a default route so let’s say I’ll take another color let’s
say there is a default route so it says default route go to r1 to r2 r2 so r1
says if you don’t know a certain route send everything back to r2 because R 2
is connected to the internet so if you don’t know something
ideally it should go to r2 and r2 will send it to the internet right so that’s
what happens now let’s assume our one does a summarization right if r1 is
doing summarization when our one sends let’s say let’s say there are network so
let me take another color let’s say there are two three two networks so
let’s say for instance t4 ten dot 1.2.0 / 24 now these two
networks are connected to our two but at our two for some reason we do Auto
summarization right summarization is enabled so what it does it does send and
we’re on a GRP and over here GRP summarization is enabled then we would
send a summary route to / 24 sorry / 8 right / ate a whole summary
route for Class A is sent to router 2 pointing to router 1 now when a traffic
comes to 10 dot 0 dot 0 R 1 I send this humble it out to our to
know our two’s a routing table points this summary route to r1 right so
let’s say if there is a traffic that is coming to 10 dot one dot dot 0 network
art would say yes I see there is a summary route I 10.000 that is not r1 so
what happens is any traffic that coming that is coming to our sh2 going to 10
dot one dot dot 0 r2 would send it to r1 and r1 would look at its routing table
and see 10 and 100 1.0 I have 1000 1.2.0 I have but now you’re asking for 10 – 1
dot 3.0 and I don’t have that way but I have a default route configured that if
I don’t know anything I will send it to our – now what our one would do r1 would
send that traffic back to r2 r2 would go back to r1 and this will go on a loop
the loop will continue until the TTL value goes to zero so there is a routing
loop that gets created because of summarization this is a problem to
prevent this every time r1 or any device in a routing protocol whenever it creates a summarization it
would create a null 0 right so it would point that summary to null zero bound by
default so if you go back we see that when now when you see now zero that’s
your clue number one through number one is there some sort of summarization
that’s happened there it could be a nought of summarization or it could be
manual summarization some summarization has happened now because now zero is
here I know our route 1 is the one who did the summarization because router 1
has advertised this summary route to its neighbors and when it advertised that it
created a null 0 so you see this it says 10.1000 slash 8 is a summary round and
it is point 2 now 0 that means if at all there is a specific route a in this case
then dot one dot 10.0 is specific it is part of the summary but that’s specific
that it tells you where it goes so if at all there are more specific routes then
the round or 2.0 3.0 5.0 10.0 whatever specific notes would get added but if at
all it’s not listed in that then this router says you know what I’m gonna send
it to null 0 let’s assume now 0 is the black hole right we know recently if
there was a black hole photo and so let’s let’s consider null 0 to be the
black hole if at all it is not there right if I know I’m the one who created
this black hole so if at all there is no specific route to a certain network that
means I’m gonna send all of them to the junkyard or to the black hole which is
going to like kill the traffic so that’s that’s a route prevention mechanism for
a dynamic routing protocol and it is done by OSPF EIGRP everybody does that
right so now I see there is a null 0 here so I know this device has done
summarization right now I’m not saying summarization is the reason why this pc1
to pc2 piece 3 is not pinging each other so at the moment will not do anything
with the summarization but we know that there is some sort of summarization has
happened right so let’s do this now let’s see let’s see if they’re
forming neighbors because I can’t see any of them with the routing protocol
any of the routes being updated so let’s go to all the device and do again the
same thing show IP route show IP route now our – you cannot also say our –
doesn’t have null 0 so our – I has not done any summarization that’s why
there’s no now 0 in r2 and let’s see r3 show IP route and we see there is D so
there’s some sort of summarization happened any HR people that’s why it
says D so in EIGRP some sort of summarization is happening in router 1
and router 3 now we don’t know if route summarization is the cause of the device
not being able to ping each other so we’re not gonna do anything with that at
the moment we’ll see why we’ll see if any show i pei GRP neighbors okay let’s
do interface let’s see okay so we see gigabit z g 0 / 0 and s z 3 so let’s see
okay so router 3 we did order to route 3 ok i can see now there is red light but
in real life you won’t be able to see red right so we’re not going to look at
the red light and do deductions or what could be wrong so we will try to see
here we see a GRP is working on three zero three zero zero zero three one so I
think this is this interface and not that so show IP show IP interface brief
and we see this is in fact down right it is down it’s not administratively down
that means there’s no problem this side let’s go here
to rot one show IP interface brief and we see this has been administratively
put down so that is one of the reason why there is no ERP that’s working on
that so let’s do this let’s go solve this problem first
technically ask ask for our diagram this should be this should be creating
neighbors right this is part of the neighbor so it’s not happening so it is
not connected it’s administered down so for some reason somebody is maybe by
mistake hit that shutdown command we don’t know
what it is but let’s go solve that now terminal interface cg 0 / 3 / 0 no shut
right so I have enabled that interface and now this interface and start
configuring and ok because we saw that EIGRP was already configured on all the
three devices so now they are starting to form neighbor so let’s do this show
IP yeah GRP again let’s write interfaces here okay so we see that zero zeros so
this is a lot of one so out of one this interface this device has become a
neighbor right we can also check show IP er GRP neighbors and we see that on the
interface 13.3 so 13.3 is this there is a neighbor right so there’s a neighbor
and 13.3 is a neighbor why is neighbor ship not farm being
formed here so that’s some things you we see that ER GRP is configured on that so
let’s say in interface we see this is also an interface so this interface is
also participating in here job if for some reason they’re not forming neighbor
ship right so let’s let’s do let’s do this show IP protocols so let’s this is
one of the commands that you should check so when you hit this you’ll get
our top level view of all the protocols that’s running
on this device so you see show IP protocols routing protocol is eigrp one
is one right so let’s let’s also look at 1 & 1 & 2 right so let’s look at two
let’s see what’s happening at two okay let’s give the same command show IP protocols okay and where’s 1 ok 1 & 3
sorry 1 & 2 ok see so this is the edge ERP one can’t
this can go back here and this can go here how this is ERP one
this eigrp 10 this is working in a is 10 and this is a s 1 so like we know the a
s should match for them to form neighbors so that is the reason why
they’re not forming neighbors another reason why neighbors may not be formed
or they may not do neighbor ship could be if the K values are different so in
this case K 1 K 2 K 3 K 4 K Phi is 1 0 1 0 0 1 0 1 0 0 but like I said CCNA level
you’re not going to go into that level so most probably this would not be a
troubleshooting tasks for you but just to be aware it should be the same so 1 0
1 0 0 should be the one if there is any authentication that’s happening between
the two devices that also could be the same if they’re not if the
authentication type and authentication passwords are not matching that could be
one of the reasons why it is not working but again authentication is also not
part of your CCNA so I’m not going to get in there so what else is different
here authorize summarization is disabled summarization is enabled like I said
summarization is not going to create problems at least not directly and
maybe I don’t know but at the moment it shouldn’t create neighbor ship problems
so this is a jar p1 and since route 3 is also a jarppi one
because route 1 and Row 3 is forming yeah everyone I think the problem is
going to be with ERP 10 because either to our ERP one so let’s let’s go and
change this to ya RP 1 so what do we do show run begin ERP and I’m gonna copy
these commands because the network command is the same I will go into
global config mode so configure terminal no router ERG RP 10 and I can say router
ERP one and then I can copy these commands or rather paste these commands
huh immediately the neighbor ship has come on
so I think that was the mistake show IP eh RP neighbors and I can see there are
two neighbors now so show IP e IG RP neighbors and there – come on so let’s
see now that they’ve become neighbors let’s see what happens
show IP route okay I can see route 1 has 10 and 20 shouldn’t you also have 30 row
30 start getting 30 ok let’s see what happens here show IP route router 2 is
got 10.20 and why is it not getting tender 10 right so so basically okay
router 20 this is by himself right row 20 router 10 is coming okay okay now
this is okay now see ya ARP the summarization is creating trouble I’ll
tell you how you could see there is load balancing that’s happening right there’s
load balancing that’s happening because this device summarization is happening
here summarization is happening here right because this device is doing
summarization this device is doing summarization so this device has a
network 10.1 dot dot 0 and he’s summarizing he has got only ten
dot one dot 10.0 and he’s summarizing 10.00 so router two is getting 10 dot 0
dot 0 dot summarization why r12 12.1 12.1 is this
and 23.3 which is this so he’s getting summarization on this and there is load
balancing happening now if load balancing is happening is going to be
very interesting so let’s let’s do this let’s say ping 10 dot one dot ten dot
zero right 10.10 right this is 10.10 and this is 30.3 so let’s
do ping 10.1 dot ten or ten and we see there is reply coming and then it’s
going destination also unreachable then reply coming and destination host
unreachable oh this is interesting because when packet comes here like
because this load balancing one is gonna be sent here one is gonna be sent here
one is so alternatively between these two links so when the first link is
being sent I’m pinging to ten dollar 1.10.10 right so the for the first
packet goes here of course there is 10.1 or 10.10 and it is coming back replies
coming back the second time when I send here it comes here it says I have no
idea who is ten dot one dot ten dot then so what happens I’m gonna send it to Who
am I gonna send it to let’s do this show IP route I note 10.1 dot so let’s say
this packet is coming standard 1.10.10 right there’s no 10.10 he has no idea
haute entertainers but he knows there is a summary address which goes to another
zero that means he’s saying you’re asking for tender 1.10.10 I don’t know
who it is but I know that this is going to null because I am going to do a loop
prevention for whatever reason because that’s a summary that I gave you right
so it’s gonna put it a null and then you’ll not so alternatively if you go
here alternatively it is going to pick the same thing should happen to 30.3 as
well so if you try 30 dot 30 it’s gonna ping once it’s gonna be destination was
unreachable destination all and pay right so that’s the interesting bit and
yes Auto summary is in fact in this case
Auto somebody is creating trouble for us so let’s go back here and remove our
auto summary so let’s go here quantity terminal router a I gr p1 no Auto
summary let’s do the same thing for out of three configure terminal router ERP
one no Auto summary right now let’s see what happen so let’s see let’s do this
gender 1.10.10 it is pinging perfectly and ten dot one dot dot 30 it is
perfectly pinging now let’s go here and let’s do show IP route and now we see
$10 1/2 10.0 20.0 and 30.0 where 20.0 is directly connected obviously 10.0 and
30.0 that is this network and this network has been advertised by E I GRP
and now it knows how to communicate so now all the devices should be able to
ping each other ping tend or 1.20 dot 20 spinning and of
course 10.10 should work now and that’s also perfect right so I think now all
the three devices should be ping HSL let’s do the same thing here thirty or
thirty twenty dot twenty eight is pinging right so this is very very
simple let’s go back to our slides so ideally when you’re doing
troubleshooting the first thing is going to be
first thing before you do all this I would say the first thing is going to be
physical connection you need no in this case there was a physical connection so
you need to look at the physical connections
is there a shutdown is there physically are all these devices talking to each
other right that’s your first number-one troubleshooting you have to check
physical connection once you do physical connection you need to you can give one
command show IP protocols that is going to give you a broad overview of the
device and all the protocols that’s running so you you have an idea so we
could we could immediately see that there was a problem because yeah our p1
and EIGRP 10 were different ace numbers and they had to be changed so that’s one
one which we you can also go into these commands that we tried show IP ERP
interface show IP EIGRP neighbor show IP a GRP topology so we can try these
commands and you know what what you see in the interface you will see whatever
interfaces that’s working on PR GRP when you do show IP EIGRP neighbors let’s
let’s quickly put those commands here so that we see it right so let’s let’s do
this show IP yeah ARP interfaces we did this
in a previous video but I’m gonna just quickly check so this will give you our
neighbors so we see that these are three interfaces that’s working on the edge
ERP and these are the two interfaces that has neighbors show IP ERP neighbors
so we can do the neighbors and we see these are the two neighbors that we have
and of course we have all this information which is which was explained
in the last video so you can always go there and check show IP ERG RP topology
which will give us our fps and feasible successors and successors and all that
information is here so these are the three troubleshooting commands but like
I said the first thing is always to check for physical connections and you
also know what null zero is so now zero is a loop prevention technique a loop
prevention is going to happen because of the summarization so to
that there is a concept called null 0 and whenever you see not 0 you need to
know that there is some sort of summarization that has happened not
always summarization is going to be a problem but if you understand
summarization is you could understand how it could be a problem right so
depending on your situation maybe it is a problem so that’s now 0 this is a
short video quickly yeah we want to just come and finish the topic so here GRP
has done now we will be getting into much more interesting topic so stay
tuned and we will see you very very very very soon so till then don’t forget to
hit that subscribe button hit on that bell icon
and don’t forget to like this video see you all very very soon bye bye

Reynold King

51 Replies to “Free CCNA | EIGRP Troubleshooting – Day 51 | 200-125 | Cisco Training”

  1. We will try to be more regular in uploading and complete this series in the next few months. Stay tuned.

  2. Wow! Finally you came back… We've been waiting for you… Thanks sooo much.. This is the only place I come to learn CCNA…

  3. why i am not be able to download the Topology,It says that unable to create order why is that happening imran sir @Networking

  4. Can you share the list of topic, from which you are seeing and making these videos. Can can you suggest me approx. time or date when this series will be finished.
    I absoultely love your your efforts and bringing your content for free to help like us (students). Really appreciate the effort.

  5. Thank you sir for these wonderful vedios.. I have learnt alot.. I have a doubt .. what is the difference between fastethernet and gigabyte ethernet?

  6. Thank you so much, have actually done ccna before. But going back and watching this training video from really refresh my memory. Waiting for CCNP. God bless you.

  7. I just got my CCNA exam passed yesterday and it's a great feeling after all the hard work that you put in. All thanks to you Imran bhai. Keep up this great work going and lead many individuals to their destinies.

  8. Dear sir, When will you release new ccna topics 200-301. i am waiting for this new ccna version vedio sir

  9. Sir, can you make a video about brief introduction on CCNA 200-301 and what is new in this course.

  10. everything is good about your videos just upload more frequently you take too much time for the next video, we have to complete this course asap and hopefully pass the exam and get certified

  11. thank you very much that give your time to people also if you can make CCNP its very good thanks in advance

  12. When you say " see you very very very soon" .. I feel like it will take minimum 6 to 8 months for your next video..

  13. Hello Imran, as always you have one of the best ccna tutorial available online and the best part is it's for free. I have learned a lot from your series and recommend your channel to my friends. So far everything on your channel is absolutely awesome but the only downside is that we have to wait for a long time for another content.
    I get it that it's not easy to make these videos but honestly the waiting period is way too long. I would pay for your complete/full series of ccna r&s. I believe that it's not only me but a lot of people might feel this way. Please reduce the waiting period. Can't wait for the "Free CCNA | ……….. – Final Day | 200-125 | Cisco Training". 😁

  14. Thanks Imran for this wonderful course of CCNA, but still waiting for new videos to cope up with the latest syllabus.

  15. Why do you call this day 51 when its been 5 years since youve started the series lool can you not count? Im not even certified and i could probaly complete this series in 1/8 of the time youve spent, finish what you started you moron

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