Let's walk through exploring this lab. I'm going to scroll down to our lab introduction right here
and click launch lab. It opens up a new tab where it starts the virtual machine and says it can take
around five minutes to get started. In my experience it doesn't but we'll wait for it to get there.
So the lab launches up and this is what it looks like. Now the majority of our terminal work is
going to be done here on server one nug. Give that a double click and what it'll do is it'll
launch basically a connection into a Hyper-V virtual machine right here which you can then WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
launch basically a connection into a Hyper-V virtual machine right here which you can then
double click to go full screen and there are our tabs. We really see R1 through R8 right here on
the screen and that's the work that we're going to be doing. Now this doesn't paint you the picture
though right and that's what you really want to see. You want to understand what is R1 and R8.
I'm going to minimize the RDP session right here by clicking minimize and right here Keith has
left us a lab topology diagram. So give that a double click and this is exactly what it looks WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
left us a lab topology diagram. So give that a double click and this is exactly what it looks
like. Now our challenge that Keith has left us ultimately is like so. We need to be able to ping
from R4 right here to the gig zero zero interface of R7. Now you can just kind of eyeball this and
see which path it should take. It should take the fastest paths possible which of course comes from WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
see which path it should take. It should take the fastest paths possible which of course comes from
the lowest cost. The EIGRP will calculate with a dual algorithm. It should go through the gig
interfaces like so. Take one hop through a fast ethernet interface then down the gig ethernet
interface down to gig zero zero. But our challenge of course is that it's not going to do that. Now
just to understand the lay of the land a little bit better let's take a look at the naming
conventions here. The way that the IP addresses are done really centers around the host names WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
conventions here. The way that the IP addresses are done really centers around the host names
right here. For instance when I see the connection between R3 and R4 you can see the third octet
is 3 4. The connection between R3 and R8 way down here the second octet here is 10.38.
The connection between R4 and R6 the third octet is 4 6 and so on and so on and so on.
So really what you want to look at when you're looking at these of course is get rid of the 10 WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
because we know that's the private address. You're really looking for a concatenation of two router
IDs right there. Now the next thing is is this is of course dot zero to indicate what subnet it is
that we're looking at. The last octet will be the number in the router ID. So for instance router 6
will be 10.246.6 and router 4 will be 10.246.4. That'll be this address right here and likewise WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
will be 10.246.6 and router 4 will be 10.246.4. That'll be this address right here and likewise
when we look at router 4's connection to router 3 we've got 10.034. This will be dot 4 and this
will be dot 3. Now again the big thing to pay attention to probably the biggest thing to pay
attention to is that we have a mix of gig ethernet fast ethernet and very slow serial connections
throughout the topology. So it's not just that there is end-to-end connectivity it's also that
it's choosing the correct path to get there that really matters. Now let's start thinking about WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
it's choosing the correct path to get there that really matters. Now let's start thinking about
what are we going to do to test and verify that everything is working. What are our commands that
we're focused in on? Of course we're going to use ping and trace route. Right out of the gate we know
that we want to establish is there connectivity and if there is what is the path that we're going
to get there. We also want to make a look at our routing table so we'll give it a show ip route
perhaps also specifying a prefix to make sure we've got a specific route that we're looking WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
perhaps also specifying a prefix to make sure we've got a specific route that we're looking
for here. Now once we've kind of got an idea of what is connected to what or you know how is it
getting there we want to start digging into what eigrp did. I really like show ip protocols
to start notice this isn't an eigrp command but it's going to give us a lot of information
about eigrp. What does it think it's doing? How does it think it's behaving? How does it think WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
about eigrp. What does it think it's doing? How does it think it's behaving? How does it think
it's configured? You get a lot of information and a lot of context right up front when you do show
ip protocols and immediately with that huge amount of information we can probably start diagnosing
things too. I'm also really going to like show ip eigrp interfaces. This is going to tell me
on this particular device what interfaces are participating in eigrp in the first place. It WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
on this particular device what interfaces are participating in eigrp in the first place. It
also tells me if it's discovered any peers off of those interfaces which will be a big tell sign too.
Keeping in the same vein of quick information I'm probably going to use at some point show
ip eigrp summary to get a quick digest of information about what's going on with eigrp
and I'll also probably dig into show ip eigrp neighbors to get more details about where we WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
and I'll also probably dig into show ip eigrp neighbors to get more details about where we
have neighbor adjacencies and what could be going on with that neighbor adjacency.
Out there in the mix is a debug command. We can always turn on debugging for eigrp
and it'll just tell you if there's any problems with eigrp right there on the terminal. I think
it's a little bit of cheating and I don't believe you'll be able to use that in a lab exam environment
so do keep that in mind but it is a way to figure out what's going on. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
so do keep that in mind but it is a way to figure out what's going on.
Now that we have that in mind what are some things that we're going to be looking for?
We're going to be looking for network statements as well as you know is this in the global eigrp
configuration or is it an address family. We're going to be looking for k values. If k values
don't match on both ends it's not going to form a neighbor adjacency. We're going to make sure our
autonomous systems match. Same drill if our autonomous systems don't match we're not going WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
autonomous systems match. Same drill if our autonomous systems don't match we're not going
to form a neighbor adjacency. We're going to be looking for passive interfaces or stub configurations
that'll be a big deal too and of course authentication mismatches if that comes up.
At some point in the skill we'll also talk about vrfs versus global routing tables
and all of these are things that could contribute to a problematic eigrp environment.
So without further ado let's start digging into the ipv4 section of this lab.