Why can't the hosts ping each other?

[Jiten87]

.pkt file is attached

I simply cannot figure this out, help!

[luis_cordova · Accepted solution]

Hi @Jiten87 ,

You must be careful with the networks that you include in the routing protocols, making sure to include all the directly connected networks(In the routers, within OSPF you need to include some networks).
I enclose the exercise works, where I indicate the networks of each link.

Also, I remind you that PCs must have a gateway in order to have connectivity with remote networks.

Regards

[Jiten87]

First off, thank you so much for replying!!

I see that I was missing the network statement "network 222.0.0.4 0.0.0.3 area 0" on R2

May I ask where you got this network from? It doesn't seem to be in my design or anything.

Thanks.

[Edwin Portillo]

Imagine that within the tests that @luis_cordova was doing, he included that address in red, but he does not have this topic in the networks of his project. If you want to delete it, enter the OSPF process and deny it:

R2
router ospf 10
no network 222.0.0.4 0.0.0.3 area 0

[Jiten87]

So I compared all configs on all routers and everything seems to be identical but I still cannot ping hosts. On your edited version, I can.

The only difference I see is on R2, image attached. Does the order of network statements in OSPF matter? Because I don't see anything else that is out of place.

Also made sure that each PC had default gateways

[luis_cordova]

Hi @Jiten87 ,

As indicated by @Edwin Portillo, that network was a test, and I forgot to remove it from the exercise.

Now, after removing it, PC networks are learned by BGP and not by OSPF, as it should be.

R2(config)#router ospf 10

R2(config-router)#no network 222.0.0.4 0.0.0.3 area 0

This happens because the administrative distance of BGP (20) is less than that of OSPF (110).

This causes the communication to be lost between the PCs, because a loop is created between R3 and R2 (this can be checked by doing the ping in the simulation mode).

To solve this, without changing much your current topology, you can change the administrative distance of OSPF, leaving it with a smaller number than BGP.
This you must configure in R3 and R2.

R3(config)#router ospf 20

R3(config-router)#distance 19

R2(config-router)#router ospf 10

R2(config-router)#distance 19

After these changes, the networks of the PCs are again learned by OSPF and have connectivity again.

Sorry if I extended a lot, but I wanted to be specific in the explanation.

Regards

[Jiten87]

Thanks for the insight, after configuring the distance on R2 and 3, I am able to ping across hosts.

Once again, very much appreciate your help!!

[Edwin Portillo]

It has configured BGP very well and also OSPF, the only thing that did not include the network that goes from R3 to R2 and vice versa (200.0.0.4).
R3 <---> R2

What you have to do is include the network in the OSPF process like this:

R3
router ospf 20
network 200.0.0.4 0.0.0.3 area 0

R2
router ospf 10
network 200.0.0.4 0.0.0.3 area 0

In addition, every final device must have a gateway that would be the interface of the nearest router in your case you did not add it:

Add them please for the two PCs

Host3

Host1

You're on the right track, keep trying, you can.