Routing problem

[HungMun]

Why cant External BGP routes propagate to internal BGP routes?

The problem cant be solved by route reflector and its only 2 routers so its already full mesh.

The S on the diagram is on different location Samoa. He's able to send his routes and IP to R1 but R2 can't get any routes from R1. What are some solutions we should do for R2 to get the routes from R1. Here is the diagram too. 

[Philip D'Ath]

Your your drawing - it will work - it will propogate those routes.

An IBGP router wont propogate routes learnt from another IBGP router.  So if you had one more IBGP router in your diagram then that last IBGP router would not get the routes - because it could only learn it from another IBGP router.

[HungMun]

any solution on how to get routes from r1 to r2 ? right now its not getting anything. 

[Sebastian Fernandez]

On R1 configure

neigh x.x.x.x next-hop-self

where x.x.x.x is the R2 peering IP

then do "clear ip bgp * soft" to advertise the prefixes 

[HungMun]

Are there any other solutions like versions are not up to date or anything else? or this should do the job? I really appreciate all the help

[Sebastian Fernandez]

Hi @HungMun 

There is no BGP restriction in propagating the eBGP route to an iBGP neighbor and that it should work. The possibilities I can think are

1. eBGP route is sent to iBGP without changing the next-hop. If R2 in the diagram does not knows about the next-hop in its routing table then in that case R2 will ignore the BGP route. Configure  R1 with next-hop-self (neighbor x.x.x.x next-hop-self) where x.x.x.x is the R1 peering IP.

2. You should some filtering configured that drops the update to R1 or on R1.

But mostly likely seem to option 1 if you are not aware of any filtering. If you can send the output for 

From R2; show ip bgp 172.19.80.201

               show run | sec router bgp

From R1: show ip route

               show run | sec router bgp

Please help rate this post if you find the answer interesting.

-

Sebastian

[Georg Pauwen]

Hello,

on a side note, post the full configs of both R1 and R2...you might be missing something else in your configuration...

[paul driver]

Hello

R2 should either have reachability for the EBGP rtr as any ebgp routes originated from this rtr will have its RID as a next-hop  or has @Sebastian Fernandez  stated you would want to specify R1 as R2 next hop for ebgp learned routes.