Hi, As far as I remember, you can set in your income filter the interface, then the gateway (in that order) to force the interface you want. On Wed, Mar 1, 2023, 02:18 Mirai Azayaka <azayaka@apernet.io> wrote:
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 <santiago@crfreenet.org> 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: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."