Hello Ilham, You can disable ECMP with `ecmp off;` in the protocol `ospfv3v6` as a workaround (if you don’t need ECMP). Since 31aa62ae6d2e111e87c08b4b27a16ead968f0689, OSPFv3 will use direct route for pointopoint interfaces. Unfortunately, kernel doesn’t support multipath with a device only route, so there is a ! on the route. BIRD v2.15 ready. bird> show route Table master4: 192.88.99.0/24 unicast [ospf2 14:55:01.553] * I (150/20) [1.9.1.9] dev wg-main dev wg-main2 Table master6: 2001:db8:272::/48 unicast [ospf1 14:55:01.553] ! I (150/20) [1.9.1.9] dev wg-main dev wg-main2 I am drafting a patch to fix it. Regards, Soha ---------------------------------------------- From: Bird-users <bird-users-bounces@network.cz> On Behalf Of Ilham Maulana Sent: Monday, March 11, 2024 12:27 PM To: Ondrej Filip <feela@network.cz>; Ondrej Zajicek via Bird-users <bird-users@network.cz> Subject: Re: BIRD 2.15 Hello, After upgrading to 2.15, OSPFv3 is broken. Previously working on 2.14. No configuration changes. This capture taken from router with Bird 2.15 installed. -------------------------------- OSPF route from router with Bird 2.15. it has ! sign. birdc show route all 2a05:abcd:abcd:abcd::/128 BIRD 2.15 ready. Table master6: 2a05:abcd:abcd:abcd::/128 unicast [ospfv3v6 2024-03-11 10:05:40] ! I (150/10) [1.1.1.1] dev wg6 dev wg7 Type: OSPF univ OSPF.metric1: 10 OSPF.router_id: 1.1.1.1 ----------------------------------------------------- OSPF route from router with Bird 2.14, working as expected, with * sign. birdc show route all 2a05:abcd:abcd:abcd::3/128 BIRD 2.15 ready. Table master6: 2a05:abcd:abcd:abcd::3/128 unicast [ospfv3v6 2024-03-11 08:23:55] * I (150/10) [192.168.99.141] dev wg2 Type: OSPF univ OSPF.metric1: 10 OSPF.router_id: 192.168.99.141 Any idea, what's going on?