Wow, thank you so much! Setting bgp_next_hop = gw; works for me! (yeah I was worried that because link-local address is interface-dependent, my router wouldn't be able to know the interface. It seems my router (also running bird) chooses the same interface as the BGP session, which is what I want.
On Tue, Feb 28, 2023 at 5:32 PM Ondrej Zajicek <[email protected]> wrote: > > On Tue, Feb 28, 2023 at 02:57:54PM -0500, Mirai Azayaka wrote: > > Hello, > > > > I am trying to send routes from my DHCPv6 prefix delegation server to > > my router using iBGP. Those delegated prefix routes on the DHCPv6 > > server are installed in its kernel table, such as 2001:db8:db8::/56 > > via <client's link-local addr>. I want to pass this information to my > > router, but what the router receive is always 2001:db8:db8::/56 via > > <global unicast addr of the DHCPv6 server>. Why would next-hop change > > if it's iBGP? > > Hello > > Because link-local address is not resolvable through IGP routing table > then it does not really make sense to keep it when propagating through > IBGP. > > I.e., the regular next-hop is valid through the whole local AS, so we can > pass it unmodified through IBGP, but link-local next-hop is valid only on > a specific link. > > Note that BIRD almost always keep bgp_next_hop attribute when it is set > manually in the export filter, so if you use something like: > > bgp_next_hop = gw; > > in prefix_delegation export filter, it should keep the value, even if it > is link-local. > > -- > Elen sila lumenn' omentielvo > > Ondrej 'Santiago' Zajicek (email: [email protected]) > OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) > "To err is human -- to blame it on a computer is even more so."
