> On 18 May 2026, at 09:21, Mike Neo <[email protected]> wrote:
>
> I think there's a problem with knowing how to access clients/internet via
> iBGP. When the ISP on R1 goes down, I can't even access the internet from R1
> via iBGP. Perhaps there's some routing missing in this area.
I would suggest providing configuration and routing table excerpts if you want
anybody on the list to help you out.
Regards,
Jeroen
>
> niedz., 17 maj 2026 o 23:43 Jeroen Massar <[email protected]> napisał(a):
>
>
> > On 17 May 2026, at 20:44, Mike Neo <[email protected]> wrote:
> >
> > Are you BGP exchanging routes between R1 and R2?
> > Yes.
> >
> > Does R1 pull/removes the routes from the upstream when they are down.
> > Yes.
> >
> > Are R2 routes visible, likely less preferred, on R1?
> > Yes, via iBGP.
>
> Then, what is the post-failover state that apparently fails?
> Check routing tables on R1 and R2, both bird and the kernel routing tables.
>
> Also do a traceroute from a client to see where things go, or if possible log
> in to each and use similar to 'ip ro get <remote-ip>' to see where the next
> hop leads. But also be sure to do that all the way from R2.
>
> Does R2 how to get to R1 to get to the clients?
>
>
> And just in case, if NAT or even normal connection tracking is involved that
> might cause issues primarily due to the missing state on R2 where those
> packets are not expected.
>
> Also this is all assuming that both R1 and R2 are announcing the same
> prefixes and that upstream keeps on sending packets.
>
> Regars,
> Jeroen
>
