IBGP and EBGP

[Ahmed Abdi]

Hi,

I was doing EBGP and IBGP configuration, i have done all the configuartions and routes to the destination is visible from

the routing table, but i am not able to ping it even if I source from my loobpack interface.

From the EBGP to IBGP the the best route is chosen.

   Network          Next Hop            Metric LocPrf Weight Path
*> 1.1.1.0/24       0.0.0.0                  0         32768 i
*> 4.4.4.0/24       192.168.12.2                           0 600 400 i
r> 192.168.12.0     192.168.12.2             0             0 600 i
*> 192.168.34.0     192.168.12.2                           0 600 i
R1#

Attached is the GNS3 topology snapshot.

Please help.

Thanks

Ahmed

[Philip D'Ath]

This could be a lot of things.  Does the destination have a route back to you?

Where does the traceroute die?  That will be a big hint.

Which router are you doing the ping from?

The route for 4.4.4.0/24 says the next hop is 192.168.12.2, but 192.168.12.0 shows there is a rib failure.  Make sure you are advertising and re-distributing 192.168.12.0/24.

[Ahmed Abdi]

Hello p.dath,

Sorry,Earlier i was trying to ping from R1 but i was suppose to start the ping from R2

destintination have a route back to R1

B       4.4.4.0 [200/0]  via 3.3.3.3(This next hop is R3), 10:06:23

Traceroute is getting stuck in OSPF Neighbor R5

R2#traceroute 4.4.4.4

Type escape sequence to abort.
Tracing the route to 4.4.4.4

  1 192.168.25.5 104 msec 144 msec 100 msec
  2 192.168.25.5 !H  !H  !H

Thanks.

[Philip D'Ath]

I think you have overly complicated things.  You are using OSPF and BGP.  You are going to need to redistribute one into the other or advertise some summarised route to make this all work.

Why not just use EBGP and IBGP?

[pabloboscariol]

Guys, why are you going to do that? Basically that is the reason to have 2 protocols, an igp to get all the loopbacks and bgp to carry internet and customer routes. Cef is in charge to resolve the recursive lookup to get the path to the bgp next hop. Ok ok this is JUST if you are using MPLS, because if you are not using MPLS, and the Intermediate routers are not aware about the 4.4.4.4 prefix, they are going to drop the packet because the forwarding is made based on the information of the IP header (and that's not the BGP next hop!)

so, said this, my question is: are you running an Mpls internet lab? Can you attach the config? Please no the that the "!H" in the trace is telling you that the router "doesn't know what to do with that destination" if you issue a show up route will see that. 

[Jon Marshall]

I'm pretty sure both Paul and Philip understand how MPLS works and what is needed if it is not being used.

The fact is the OP makes no mention of MPLS so you are making assumptions about both the OP's question and the answers provided.

He may well be using MPLS but it would be better just to ask than tell everyone else they are wrong.

Don't comment on ratings often but cannot see how Philip's answer was unhelpful at all (+5 to try and adjust).

Jon

[pabloboscariol]

yes Jon you're right. I didn't try to say that somebody doesn't know how this works, I just was writing from mobile and went overexcited talking about mpls stuff :P

as they said, if you run just IP, redistribute on the IGP to get IGP timers, or just use BGP.

[Jon Marshall]

No problem, it was probably just the way it was worded.

I can understand why a CCIE SP would be excited about MPLS :)

Jon

[paul driver]

Hello

I can see rib failure for the next hop this basically is say bgp hasn't the best route for this prefix do you have and igp or static advertising a better ad distance?

Also turn off bgp sychronisation and apply an ibgp peering between r5 and r6 to provide a full mesh ibgp configuration 

res

paul

[Muditha Dasanayake]

Hi,Ahamad

Please check with destination routing table weather the source address is it. When you ping from source address even from your loopback, 1.1.1.1 from R1, but from the destination ex :R4, routing table ,if 1.1.1.1 is not there , ultimately drop the packet.So please check with destination routing table