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Welcome to this troubleshooting video.

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This is one of multiple videos that you'll find on my YouTube channel which helped me prepare for the

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CCMA petition.

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Now we've been told in this apology that P.S. 1 is not able to ping P.S. 2.

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So let's do some investigation in this example P.S. One is actually in Iowa's router so I'm running

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Iowa's V with ingenious 3 show IP raft shows us that there are no rafts on this road.

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Acting as a P.C. if you see outputs such as this default gateway is something and the IP routing table

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isn't displayed but you see something such as ICMP redirect caches empty.

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It's probably because routing has been disabled on this router so noticed this command no IP routing

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that simply turns this round into an expensive a very basic P.C. so if it was a physical router you

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essentially disabling the functionality of the router can.

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P.S. 1 ping P.S. 2 based on information that we've been given.

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As you can see in the output it's not able to ping P.C. to notice we're getting you dot you dot u u

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means unreachable.

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That means that P.S. 1 is forwarding traffic to a router which could be right of 1 and that drought

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it doesn't have a route to the remote network that does host resides on now to speed things up I'm going

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to use the command no IP domain lookup and then I'm going to trace route 2 tendered 1 or 3 to 2 so notice

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we are able to get to road 1 10 1 1 1 but road one doesn't know where to forward the traffic so there

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seems to be a problem on Route 1.

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So not a one show IP interface brief.

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This looks correct.

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This IP address is configured on this interface gigabit.

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0 1 this IP address is configured on this interface gigabit 00 can write a 1 ping router to.

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The answer is yes it can.

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Initial ping failed because it was doing an op for the MAC address of rider to so let's have a look

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at the writing table show IP brought in the output we can see that we only have connected ruts and local

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routes no other routes have been learnt.

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We only see Network 10 1 1 0 and Network 10 1 2 0 slash 24 and the local host addresses on the interfaces

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of the road.

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We don't see a network 10 1 2 3 0.

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Are we running a routing protocol on this router so show IP protocols shows us that we are running a

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routing protocol in this case it's always P.F. process 1 Rada idea of the router is this.

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It's an area border router it has an interface gigabit 0 0 in area 0.

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In other words this network here is an area 0 and this interface gigabit is 0 1 is an area 1 show IP

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SPF interface brief is another useful command.

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This gives us brief information so we can see that gigabit 0 0 with 0 SPF process 1 is in area 0.

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We can also see the IP address and subnet mask used on that interface subnet masks need to be the same

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IP version 4 for Rogers to form a neighbor relationship gigabit 0 1 is in Area 1 of 0 SPF process 1

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and it's got this IP address.

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Show IP 0 SPF.

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Neighbor know neighbor relationships have been formed so SPF is running on gigabit.

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0 0 overall to 1 but is not forming a neighbor relationship with 4 out 2.

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So let's have a look at draw to t and see if we can find a problem.

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Show IP protocols always be a process one is running on this rota and in the output can you see the

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problem.

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You should already be able to determine the problem by that output but I'll also use this command show

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IPO SPF interface brief to help me can you see the problem notice on Route 1.

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This interface gigabit 00 is an 0 SPF area 0 on Rod a 2 gigabit.

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0 0 is an area 2.

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It's a requirement in 0 SPF that both sides of the link be configured in the same area so show run interface

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gigabit 0 0 shows us that this interface has been configured in 0 SPF process 1 but in Area 2 whereas

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on the side show run interface gigabit 0 0 shows us that that interface is an area 0 so to fix this

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we need to change the area to area 0 so to show run interface gigabit 00 notice the ISP f area has changed

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show IP SPF interface brief the area has now been set properly show IP protocols shows us now that this

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interface is an area zero where as gigabit 0 1 is an area to show IP of SPF neighbor a neighbor relationship

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has been established.

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Now why were we not seeing output on the screen one of the reasons for that is that a logging could

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be disabled so do show run pipe include log notice this command has been added to the running config.

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No logging console.

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I added that on purpose so that you didn't see warning messages on the screen to help you determine

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what the problem was.

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So now as an example if I shut down gigabyte 0 0

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or rather I should remove the no logging console and enable logging and now go onto the interface and

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shut it and then no shut it.

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We should see output.

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As in we should see that the interface comes up and there you go.

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And we should see that.

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Who is Peer.

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Relationships are formed and there you go.

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Be careful of your logging.

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If you telnet or SSA to Radha don't forget to use the command to Mun so that you see logging on the

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Viti y lines.

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Logging is enabled by default on the console.

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But I had purposely disabled it so things are looking better.

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We have a neighbour relationship show IP of SPF neighbor shows us that on the side show IP who is always

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SPF neighbor.

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Neighbor relationship is there show IP wrote notice we now see an entire area always appear from 8 to

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10 1 3 0 via 10 1 2 2.

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So can the shrouded ping the remote P.C..

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Yes it can.

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Can P.S. 1 ping the remote.

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Yes it can and when we do a trace that's also successful let's test in the reverse direction just to

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make sure everything is good.

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That looks fine.

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Notice the problem is trace right.

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If you don't disable IP domain lookup the trace Rod is going to take a long time while it tries to resolve

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the names so I've disabled the trace no IP domain

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lookup through the trace again notice it's a lot quicker now because it's not doing a domain lookup.

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I'll do that again.

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There you go.

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So P.S. 1 since traffic to write a 2.

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And then it sends traffic to road 1 and it then hits the destination

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so that was an example of troubleshooting 0 SPF.

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Don't forget that with 0 SPF you can configure it.

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One of two ways you can configure it on an interface as I've done in this example or you can use the

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network command under the running process I'll leave the troubleshooting of match to a separate video.

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So if you get a simulation in the exam make sure that you check that 0 SPF areas have been configured

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properly.

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Thanks for watching.

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Let me know which videos you want me to record.

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And don't forget to subscribe.

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All the very best.