Incorrect iBGP next hop in bird2

21 Dec 2020

      Hi,

I've very simple install.
Server with two links vlan1 - 50.0.0.1/25 and vlan2 - 10.0.0.7/31
One static default route and one iBGP neighbor:

protocol static default_route {
        ipv4;
        route 0.0.0.0/0 via 50.0.0.254;
}

protocol bgp nat_downlink1 {
        local 10.0.0.7 as 65001;
        neighbor 10.0.0.6 as 65001;
        #direct;

        ipv4 {
            next hop self;
            import all;
            export all;
        };
}

Neighbor sends me a bunch of /32 host routes and all routes received from 10.0.0.6 neigbor has next hop 50.0.0.254.

bird> sh route
Table master4:
0.0.0.0/0            unicast [default_route 15:23:28.170] * (200)
        via 50.0.0.254 on vlan1
10.107.1.81/32       unicast [downlink1 16:59:19.320 from 10.0.0.6] * (100/?) [i]
        via 50.0.0.254 on vlan2

To fix this I can add direct option to me BGP neigbor, but I wonder why this even happens.
Is there more correct eay to fix this?

Юрий Иванов

Ondrej Zajicek

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