We have a lab and we have an objective, but I actually want to tweak that objective just a
little bit. Router1 actually has multiple loopback addresses. So what I want to do is I want to see
if we could ping to maybe not the exact same loopback address that I originally intended,
like 1111. Maybe we want to ping to something like 1114. Here, let me go full screen here
and show you. If I give it a show IP interface brief like this, hit spacebar, let's see if we
can ping to 1114. So if I jump all the way to router10 right here, give it a show IP interface WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
can ping to 1114. So if I jump all the way to router10 right here, give it a show IP interface
brief, we can see we have 10.10.10.10 right here with loopback1. If I ping 1.1.1.4 sourced from
loopback1, not making it there. Not making it there. Let's see where it dies. Traceroute
to 1.1.1.4. Not making it anywhere. We're not even going one hop. Give it a control shift six WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
to 1.1.1.4. Not making it anywhere. We're not even going one hop. Give it a control shift six
to exit out of that traceroute. Let's do a show IP route. And that's why I don't have a route
for 1.1.1.4. So that makes me question if it's being advertised from R1 in the first place.
Let's see, if we're advertising these via BGP, let's do show BGP IPv4 unicast. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
Let's see, if we're advertising these via BGP, let's do show BGP IPv4 unicast.
And let's just look and see. Okay, I am beginning to think that I'm not advertising this route at
all. Do I even have a neighbor adjacency? Show BGP IPv4 unicast neighbors. Neighbors. There we go.
Okay. I do see a BGP neighbor right here. And I do see a sent and received prefix. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
Okay. I do see a BGP neighbor right here. And I do see a sent and received prefix.
That's going to tell me right out of the gate that we do have a healthy neighbor adjacency
with our peer over here, 1.7.2.16.12.2. We can also do this. We can do neighbors 1.7.2.16.12.2.
And let's take a look at advertised routes. And now, yeah, okay. So right here, when I look at WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
And let's take a look at advertised routes. And now, yeah, okay. So right here, when I look at
this neighbor, 1.7.2.16.12.2, and I look at the routes that I'm advertising to them, I can
immediately see I'm not even advertising 1114 to my directly adjacent neighbor. So we need to
figure out why that is. So let's see why we're not advertising that route. One of the easiest
ways we can do that is just look at our configuration. Show run section BGP. We know
this is a big command, so we got to let it parse through the output before it actually renders on
the screen. And, well, that's why we're literally not advertising the route to our neighbor. Okay. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
the screen. And, well, that's why we're literally not advertising the route to our neighbor. Okay.
Config T, router, BGP for autonomous system 100, network 1.1.1.4 with all bits on for our loopback.
Yeah. Uh-oh. Uh-oh. Mask. Forgot mask. I always do that. I always forget mask, y'all. Okay. There
we go. So now that we're advertising this, you know, it should make this work. We can do a soft WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
we go. So now that we're advertising this, you know, it should make this work. We can do a soft
inbound reset if we need to. Clear BGP IPV4 unicast inbound. No, no, no, no, no, no, no, no.
Specify our neighbor adjacency 16, 12, 1, N, like that. Okay. Now when I look at my show IP route
table, I should see, ah, 1114. Let's see if it made its way all the way over to router 10 yet. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
table, I should see, ah, 1114. Let's see if it made its way all the way over to router 10 yet.
Show IP route. And now we have 1114. All right. Okay. So we might be done. Let's take a look at
traceroute here. Makes its way into the confederation. The first confederation between
routers eight and nine. And then not looking good. Looks like it dies as soon as it enters
AS300's 65,200 confederation. So let's take a look at this from router nine because router nine WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
AS300's 65,200 confederation. So let's take a look at this from router nine because router nine
is the one that advertises and we know it got the route, right? If I do show IP route,
we know it got the route and forwarded that via EBGP to its peer in AS400. So why is the ping dying?
So let's, let's minimize this RDP session and take a look at the topology one more time. I want to
see this. Okay. So this is interesting because when it makes its way into router nine and then WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
see this. Okay. So this is interesting because when it makes its way into router nine and then
it's trying to go to router eight, but it might've expected it to actually go straight to router seven
and pass through the confederation that way. That's probably what I would have expected to
see it do. Hmm. Cause let's take a look at this now. Let's jump back here to router nine.
When I look at this route, it's coming from router four, five. So it's going into router
four, five. Let's do show IP, show BGP IPV4 unicast summary. Ah, the plot does thicken. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
four, five. Let's do show IP, show BGP IPV4 unicast summary. Ah, the plot does thicken.
Look at this right here. My neighbor between seven and nine, that's going up to the next confederation
is currently in an idle state. Hmm. So definitely something wrong with router seven and router nine.
Let's take a look at our configuration here. Make sure the confederation is configured correctly on
router nine. Got to wait. You know, it's a big command. It takes a while to run. Be patient. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
router nine. Got to wait. You know, it's a big command. It takes a while to run. Be patient.
Okay, here we go. Correct autonomous system, correct confederation, specified our confederation
peer, correct neighbor statements and network statements. So I don't see anything on router
nine. Let's take a look at this. We'll do show run section BGP from router seven's perspective
and see how it's configured in the other confederation. Oh, okay. All right. Look at this. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
and see how it's configured in the other confederation. Oh, okay. All right. Look at this.
So because I specified address family IPV4, that means we are supposed to put statements under the
address family IPV4, especially when used in conjunction with no BGP default. Because when
we type these commands like neighbor statements, it's thinking, okay, well, I'm defaulting to IPV4 WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
we type these commands like neighbor statements, it's thinking, okay, well, I'm defaulting to IPV4
unicast. But when we say, hey, don't default to IPV4 unicast, then it needs to be put in the
address family IPV4. And as you can see, I've got a neighbor statement for six, seven. If you got
young kids, I'm sorry, this day and age, it's all mine. So six, seven, anyways. All right. So
then we would also need this neighbor statement right here to be activated.
Config T, router BGP, six, five, 100, address family IPV4, WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
Config T, router BGP, six, five, 100, address family IPV4,
IPV6, four, neighbor 10, zero, 79, nine, activate. There we go. Now press end here,
neighbor adjacency is up. Ah, okay. Better, better, better, better, better. Let's do show
BGP IPV4 unicast summary. Now I see the neighbor adjacency and I see prefixes received. Ah, WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
BGP IPV4 unicast summary. Now I see the neighbor adjacency and I see prefixes received. Ah,
okay. Okay. Okay. All right. All right. That's good. Let's try and go back here.
Do our trace route again. Oh, okay. We got from one end to the other. However, look, look, look,
look at the route that it took. It went down to four instead of three, four. It went down the
fast ethernet link instead of the gig ethernet link. So something tells me that, you know, WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
fast ethernet link instead of the gig ethernet link. So something tells me that, you know,
something is afoot, if you will, with this link and this neighbor adjacency right here. So let's
minimize this, jump back here. Let's take a look at this from our force perspective, show BGP IPV4
unicast summary. Okay. Got a neighbor adjacency between three. Oh, do you see it? Neighbor
adjacency is there. Good. No prefixes received. Okay. I'll tell you exactly where my head goes WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
adjacency is there. Good. No prefixes received. Okay. I'll tell you exactly where my head goes
when I see this. And I think route reflector. Why am I thinking route reflector? Well, because
where are these prefixes going to come from? If I bring up the topology here, you know,
let me undo. Okay. So we want to get to this loop back on R1. R1 has an IBGP relationship with R2.
What is the IBGP methodology for sharing IBGP learn route? You don't. You don't forward IBGP WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
What is the IBGP methodology for sharing IBGP learn route? You don't. You don't forward IBGP
learned routes to IBGP peers. You do forward them to EBGP peers. So if R2 isn't a route reflector,
R11 and R3 are never going to learn about R1's routes. So let's figure out what's going on here.
Let's take a look because that's where my head goes. We got to get a pin going, get this back,
go into R2. And so from R2, well, first let's see, you know, we know, let's see if show BGP WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
go into R2. And so from R2, well, first let's see, you know, we know, let's see if show BGP
IPv4 unicast summary. Just make sure. Yeah. So we do have a peering relationship between two and three.
Interestingly, we do see three prefixes received, but if I do show IP route, none of them are those
1111 addresses that R1 is advertising to two. So if I look at R2's configuration,
show run pipe section BGP. Yes. It's going to hang for a little bit more. WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
show run pipe section BGP. Yes. It's going to hang for a little bit more.
Bear with me. That's worth the wait.
There we go. Yep. We're not, we don't have any route reflector clients configured for R2.
So I'm going to go into R2 and say, Hey, if you get routes from R1, that's your route reflector
client. You need to bounce those on. Let's go to config T, router, BGP 100. Nope, not BGO, BGP,
neighbor 172.16.12.1, route, reflector, client. End right there. Topology changed, WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
neighbor 172.16.12.1, route, reflector, client. End right there. Topology changed,
topology up. Let's look at router three one more time. Just hit up for show IP route.
There's the route. Now that we have that route going through R3, R3 is going to advertise that
up to R4 and then things like highest loopback will be the tiebreaker, I think. And sure enough, WEBVTT X-TIMESTAMP-MAP=MPEGTS:0,LOCAL:00:00:00.000
up to R4 and then things like highest loopback will be the tiebreaker, I think. And sure enough,
that's exactly what we get right there. Now we go through the confederation perfectly
down through router three, and then ultimately to router one. We did it. Awesome. Now onto the
next lab.