Thanks Charles, Alexander.

I disabled the rp_filter. it works.

By the way,
I  have made a  opensource Virtual Network Topology builder (Bird running  in dockers, and we can make a any kind of topology).
Please have a look on this quick tutorial, and share your feedback.

https://www.youtube.com/watch?v=PEdc6uwNkr0&t=25s

https://github.com/knetsolutions/knet/

Thanks
suresh

On Tue, Apr 24, 2018 at 9:35 PM, Alexander Zubkov <green@qrator.net> wrote:
Hi.

Try to disable rp_filter first.

On Tue, Apr 24, 2018 at 5:16 PM, knet solutions <knetsolutions2@gmail.com> wrote:

All,

I am facing a strange issue (all routers are linux with bird runnning).
My topology(RING Topology) is as below,


R1 ------------R2------------R3---------R4

BGP is running on all nodes.

R1 to R3 route is going via R1--R2--R3 and the return path is in also in same path (R3--R2----R1), then  thing works fine

But suppose,

R1 to R3 path is  R1---R2---R3 and  return path is  R3----R4---R1.  then  traffic is not passing.

Any configurations i should do in linux ?




--
Regards,
Knet solutions.

https://github.com/knetsolutions/KNet
http://knet-topology-builder.readthedocs.io/
http://knetsolutions.in/