(music)
- Alright so here we are zipping along now in part three
and now we're gonna add EIGRP to what we've already done
so far in parts one and part two.
So let's go back to our original requirements here.
I'll put my topology back in here.
So we know that everything's supposed to be in
one autonomous system.
It was not specified what that autonomous system should be
so it's up to you, I'm just gonna use
EIGRP autonomous system 100,
but you can choose any number that you wish.
And we also know that EIGRP is supposed to be configured
on all of these devices, adding every single link
into the process.
Okay, so let's go ahead and do that.
So let's start up everything,
let's open it up once again SecureCRT.
Alright, let's start with router one.
conf t, router eigrp 100.
Now this point, here's a little shortcut,
the CCNA doesn't necessarily expect you to
know how to do this and they probably wouldn't
want you to do this on any simulations
but if you do desire to have every single interface
in your router in the EIGRP protocol,
you can simply type network 0.0.0.0
and that covers all of them at once.
But for the purposes of the CCNA Routing & Switching Exam,
they're gonna want you to be a little bit more specific
than that.
So we're gonna use the actual explicit networks
along with wildcard masks.
(key strokes)
Alright and that completes our EIGRP configuration
in router one.
Alright, so we've saved our configuration there
so we can go ahead and get rid of that guy,
get rid of his window.
Now where are we right here?
Which router is this?
This is router four, okay,
so we'll go ahead and do the same thing,
router eigrp 100,
network 44.44.44.0,
that covers our loopback.
network 2.4.2.0
and network 3.4.3.0
and save our configuration.
And show ip protocol can verify the EIGRPs configured
and that has been configured on the correct networks
for this particular device.
Alright so save it, get rid of router four
and now who do we have?
Router three, okay, router eigrp 100.
Now in this particular router, one of the things
that we were asked to do was to use
the built in capabilities of Wireshark built into GNS3
so we could actually capture some packets
and see what's going on
and I would prefer to do that
across the Fast Ethernet links.
That way we can also see the multicast addresses
that are used and the MAC addresses and all that good stuff.
And we wouldn't see that stuff if we do our packet captures
on the serial interfaces.
So in this particular case here's what I'm gonna do,
I'm gonna go ahead and complete the configuration
between router one and router three,
I'll enable this link in EIGRP so the neighborship
will come up, but before I add this link
into this,
I'm gonna go ahead and turn on Wireshark
on this interface which I think is Fast Ethernet 0/1
in router three and then we'll see that
when I add EIGRP to this link, we'll actually be able
to capture the packets as the whole neighbor relationship
is built and as the EIGRP updates are exchanged.
So, let's go ahead on router three here
and add in the command to...
add EIGRP into the link connecting
to router one.
Alright, we should see that neighborship
come up pretty quickly.
There we go.
Alright, and now before I do the final stage of this,
let's go back to our GNS3 topology...
and I'm going to right-click
and select capture
and that will enable me to start Wireshark.
Now when I do that, it's gonna ask me
"Which interface do you want to capture on?"
In this particular case it's defaulting to the one
I actually did want, Fast Ethernet 0/1, that's good.
So now just hit okay
and Wireshark will come up immediately
and start capturing packets.
Alright so let's go to router three
and finish off our configuration.
network 3.4.3.0.0.0.0.255
save our memory and we can see that already
the EIGRP neighbor relationship was built.
So we can go ahead and go back to Wireshark
and stop capturing, so we don't need to anymore.
There we go.
Now, if there were other routers on this link
for example if there were three or four routers or something
I might say well, "I only wanna see the EIGRP packets
"that were either transmitted from or received by
"router three."
So let's imaging there were two or three other,
maybe this link is connected to a hub or a switch
or something, I'd say.
"Oh, I don't wanna see all their packets going back
"and forth, I just want to see the ones going to
"or coming from router three."
So that involves creating actually a Wireshark filter.
So here within the upper left corner of Wireshark
is where I'm gonna create that filter.
It's just ip.addr and then ==
and then the IP address,
in this case 3.4.3.3.
Alright and so now this will show me,
this will filter out everything and only show me packets
where 3.4.3.3 was either in the source
or the destination, since I didn't specify that.
And so we can see, here's the exchange of hellos
between router three, router three,
and now once the link comes up
here is an update that goes across.
So let's go back to the hello first.
We can open that up and see some pretty good stuff.
You can see here that it's using
the 224.0.0.10 as the destination
and its own IP address as the source
and if we scroll and also we can see
that the IP protocol is Protocol 88,
that's the protocol reserved for EIGRP.
This is all stuff you could be potentially tested on
for the CCNA.
And if we scroll down to the actual body of the EIGRP packet
right behind the IP header we can see
all this good stuff.
So we can see the operational code is Hello, this is a Hello
and in the Hello the CCNA is gonna expect you to know
what is in the Hello and what parameters have to match
and what parameters don't necessarily have to match.
Well we know the autonomous system numbers in there,
that has to match and we also know that
under the parameters field, what's called the K Values
have to match,
And we see all that right here.
Alright so let's go ahead and shut down Wireshark,
we don't need that anymore
and before we exit out of this video.
Let's make sure at this point...
router one should know about, actually router three,
router three should know about everything.
He should know about the loopback of router one
and the loopback of router four,
sho ip route.
And we can see, he does.
And further more at this point we should have
end to end reach-ability.
So if I close out this and now here we are
at router two, well we don't really care about
router two anymore, he should be all good to go.
Let's just make sure that he's configured appropriately.
Nope, router two doesn't have any configuration
for EIGRP.
(key strokes)
Okay, so router two is done.
So now at this point , if we go into router one,
just double-clicking on him
and do sho ip route...
issue that command...
we can see that router one has learned about
router four's loopback.
And we should be able to ping it,
and we can.
And we can also see that as far as that loopback
is concerned, the path that's been learned,
or I should say the preferred path
is Fast Ethernet 0/0
which makes sense because that path is faster than
the serial link on top.
Now that leads us to ask the question
you might be asked in the CCNA,
how would you discover all of the possible paths
that a router has learned
to a particular destination network?
Well you should know the command sho ip eigrp topology
which gives you a high-level sort of summary view.
And looking at this you might initially think,
"Oh, well router one only has learned about the
"44 network via the Fast Ethernet path,
"something must be wrong because why didn't he also
"learn about the serial link, even though
"that might not be the link he's actually using
"in his routing table, it should still be in here right?"
Remember, this particular command, only shows you
your successors and feasible successors.
Now if you don't know what those terms are,
better go look 'em up because that's something
the CCNA Routing & Switching Exam is gonna expect
you to know what those terms are.
So this only shows you successor and feasible successors.
There's a possibility that you could learn of an alternate
path to route that doesn't meet either one of those
conditions.
It's not a successor or a feasible successor, why?
Well, if an incoming route comes to you
and it does not meet the "feasibility condition"
which is the condition that EIGRP uses
to try to detect routing loops.
If it does not meet the feasibility condition,
it will not be classified as either a successor
or a feasible successor.
So how can we tell in our topology table
if we actually have learned about this route
via the serial link but because it came in
and the metric was so horrible, it was considered
as a possible loop and it did not meet
the feasibility condition.
Well here's how we can tell,
we can use that exact same we just used,
but with a keyword of all-links.
And now we can see as far as the 44 network is concerned,
yes the Fast Ethernet 0/0 is the successor
but here it is down here and wow, why didn't this
be considered?
Well look at this, right now our feasible distance,
our total distance for the best, fastest path
is 435,200.
Well our neighbor downstairs on the serial link,
he advertised a path of little bit of over two million
as the metric.
That does not meet the feasibility condition.
And if you wanna know more about the feasibility condition,
you definitely wanna research that,
because that is also CCNA Routing & Switching level topic.
So at this point,
that concludes this particular section
of the video where we've done our basic EIGRP configuration.
So stay tuned for the next videos coming up
to add the authentication element into this
and then lastly we're gonna manipulate EIGRP
so it actually prefers that slower path on the top.
(music)