Hello Mikrotik community,
I am struggling with the route selection process of RouterOS on a RB1100AHX2, ROS v6.44.3.
I have 3 default GW, one received through a PPPoE FTTH link (n°2), one by BGP through a GRE tunnel over the FTTH link (n°3), and the last one by BGP through a dedicated fiber link (n°1) :
1 ADb dst-address=0.0.0.0/0 gateway=147.78.145.25 gateway-status=147.78.145.25 reachable via Interco WAN HQ-PAR2 distance=100 scope=40 target-scope=10 bgp-as-path=“209323,8309” bgp-med=500 bgp-origin=igp
bgp-communities=65535:8309 received-from=rt1-par2
2 DS dst-address=0.0.0.0/0 gateway=Orange Fibre PPPoE gateway-status=Orange Fibre PPPoE reachable distance=250 scope=30 target-scope=10
3 Db dst-address=0.0.0.0/0 gateway=147.78.145.26 gateway-status=147.78.145.26 reachable via Interco WAN HQ-PAR2 distance=100 scope=40 target-scope=10 bgp-as-path=“209323,1299” bgp-med=500 bgp-origin=igp
bgp-communities=65535:1299 received-from=rt2-par2
The idea is to go first through the dedicated fiber, then through the GRE tunnel and in last resort directly through the FTTH.
As expected, here, the route n°1 is active (best BGP route, shortest distance).
But if I shut down the fiber link, here is the situation:
1 ADS dst-address=0.0.0.0/0 gateway=Orange Fibre PPPoE gateway-status=Orange Fibre PPPoE reachable distance=250 scope=30 target-scope=10
2 Db dst-address=0.0.0.0/0 gateway=147.78.145.20 gateway-status=147.78.145.20 reachable via gre-hq-par2 distance=220 scope=40 target-scope=10 bgp-as-path=“209323,8309” bgp-local-pref=70 bgp-med=500
bgp-origin=igp bgp-communities=65535:8309 received-from=rt1-par2 via GRE
The route through the FTTH link (n°1) takes precedence over the GRE tunnel (n°2), even though it has a higher distance. That does not seem right to me. I have been tuning distances, BGP local-pref and weight for a few hours, but haven’t been able to make the router act as expected.
Does anyone has a clue about what is happening here ?
Hervé