Welcome to this troubleshooting video.
This is one of multiple videos that you'll find on my YouTube channel which helped me prepare for the
CCMA petition.
Now we've been told in this apology that P.S. 1 is not able to ping P.S. 2.
So let's do some investigation in this example P.S. One is actually in Iowa's router so I'm running
Iowa's V with ingenious 3 show IP raft shows us that there are no rafts on this road.
Acting as a P.C. if you see outputs such as this default gateway is something and the IP routing table
isn't displayed but you see something such as ICMP redirect caches empty.
It's probably because routing has been disabled on this router so noticed this command no IP routing
that simply turns this round into an expensive a very basic P.C. so if it was a physical router you
essentially disabling the functionality of the router can.
P.S. 1 ping P.S. 2 based on information that we've been given.
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
means unreachable.
That means that P.S. 1 is forwarding traffic to a router which could be right of 1 and that drought
it doesn't have a route to the remote network that does host resides on now to speed things up I'm going
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
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
seems to be a problem on Route 1.
So not a one show IP interface brief.
This looks correct.
This IP address is configured on this interface gigabit.
0 1 this IP address is configured on this interface gigabit 00 can write a 1 ping router to.
The answer is yes it can.
Initial ping failed because it was doing an op for the MAC address of rider to so let's have a look
at the writing table show IP brought in the output we can see that we only have connected ruts and local
routes no other routes have been learnt.
We only see Network 10 1 1 0 and Network 10 1 2 0 slash 24 and the local host addresses on the interfaces
of the road.
We don't see a network 10 1 2 3 0.
Are we running a routing protocol on this router so show IP protocols shows us that we are running a
routing protocol in this case it's always P.F. process 1 Rada idea of the router is this.
It's an area border router it has an interface gigabit 0 0 in area 0.
In other words this network here is an area 0 and this interface gigabit is 0 1 is an area 1 show IP
SPF interface brief is another useful command.
This gives us brief information so we can see that gigabit 0 0 with 0 SPF process 1 is in area 0.
We can also see the IP address and subnet mask used on that interface subnet masks need to be the same
IP version 4 for Rogers to form a neighbor relationship gigabit 0 1 is in Area 1 of 0 SPF process 1
and it's got this IP address.
Show IP 0 SPF.
Neighbor know neighbor relationships have been formed so SPF is running on gigabit.
0 0 overall to 1 but is not forming a neighbor relationship with 4 out 2.
So let's have a look at draw to t and see if we can find a problem.
Show IP protocols always be a process one is running on this rota and in the output can you see the
problem.
You should already be able to determine the problem by that output but I'll also use this command show
IPO SPF interface brief to help me can you see the problem notice on Route 1.
This interface gigabit 00 is an 0 SPF area 0 on Rod a 2 gigabit.
0 0 is an area 2.
It's a requirement in 0 SPF that both sides of the link be configured in the same area so show run interface
gigabit 0 0 shows us that this interface has been configured in 0 SPF process 1 but in Area 2 whereas
on the side show run interface gigabit 0 0 shows us that that interface is an area 0 so to fix this
we need to change the area to area 0 so to show run interface gigabit 00 notice the ISP f area has changed
show IP SPF interface brief the area has now been set properly show IP protocols shows us now that this
interface is an area zero where as gigabit 0 1 is an area to show IP of SPF neighbor a neighbor relationship
has been established.
Now why were we not seeing output on the screen one of the reasons for that is that a logging could
be disabled so do show run pipe include log notice this command has been added to the running config.
No logging console.
I added that on purpose so that you didn't see warning messages on the screen to help you determine
what the problem was.
So now as an example if I shut down gigabyte 0 0
or rather I should remove the no logging console and enable logging and now go onto the interface and
shut it and then no shut it.
We should see output.
As in we should see that the interface comes up and there you go.
And we should see that.
Who is Peer.
Relationships are formed and there you go.
Be careful of your logging.
If you telnet or SSA to Radha don't forget to use the command to Mun so that you see logging on the
Viti y lines.
Logging is enabled by default on the console.
But I had purposely disabled it so things are looking better.
We have a neighbour relationship show IP of SPF neighbor shows us that on the side show IP who is always
SPF neighbor.
Neighbor relationship is there show IP wrote notice we now see an entire area always appear from 8 to
10 1 3 0 via 10 1 2 2.
So can the shrouded ping the remote P.C..
Yes it can.
Can P.S. 1 ping the remote.
Yes it can and when we do a trace that's also successful let's test in the reverse direction just to
make sure everything is good.
That looks fine.
Notice the problem is trace right.
If you don't disable IP domain lookup the trace Rod is going to take a long time while it tries to resolve
the names so I've disabled the trace no IP domain
lookup through the trace again notice it's a lot quicker now because it's not doing a domain lookup.
I'll do that again.
There you go.
So P.S. 1 since traffic to write a 2.
And then it sends traffic to road 1 and it then hits the destination
so that was an example of troubleshooting 0 SPF.
Don't forget that with 0 SPF you can configure it.
One of two ways you can configure it on an interface as I've done in this example or you can use the
network command under the running process I'll leave the troubleshooting of match to a separate video.
So if you get a simulation in the exam make sure that you check that 0 SPF areas have been configured
properly.
Thanks for watching.
Let me know which videos you want me to record.
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All the very best.