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Morus
Morus
New Member
May 30, 2025
Solved

SDWAN BGP on Looback (Dynamic) + ADVPN 2.0 info

  • May 30, 2025
  • 1 reply
  • 915 views

Hello to all,
I’m trying to build a single spoke hub & spoke (Dual hub) topology using the overlay template provided by FMG 7.6.3.
The architecture is formed by 2 VM fortigate hubs in 7.4.6 and an onprem A/S pair that acts as spoke in 7.4.6.

Full internet topology, each hub has only one link while the spoke has 2.
All the tunnels are UP, and HUB side I see the advertisement in BGP of the test subnet that I’m using onprem side (192.168.99.0/24).

 

The BGP advertisement has something strange, I would have expected to see the VPNs as next-hop interfaces, instead it uses directly the port 1 (outside of the hub) used by the underlay.

Immagine 2025-05-30 105102.png

I noticed that the templates created by FMG do not assign an IP on the HUB interface tunnels, I don’t know if this is an error.
From the hub loopback (172.16.5.252) I can successfully ping the spoke’s Lo (172.16.5.1).

Best answer by Morus

I figured out the issue, so basically the RR client was turned on the branch side. so i removed that configuration and the routes was advertised correctly.

1 reply

xshkurti
Staff
xshkurti
Staff
May 30, 2025

You can change the behavior of BGP on Hub by configuring set next-hop-self under bgp peers.

How to modify BGP next hop for route refl... - Fortinet Community

This way, the hub will advertise learned routes as they were locally available.

Morus
MorusAuthorAnswer
New Member
May 31, 2025

I figured out the issue, so basically the RR client was turned on the branch side. so i removed that configuration and the routes was advertised correctly.

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