On Wed, Sep 21, 2022 at 08:47:03AM +0000, Mazur, Dariusz wrote: > Hello Ondrej, > Thanks for quick response. Additional option to ignore link-local BGP next > hops would help us a lot.
Hello Done, here is a commit with BGP channel option 'next hop prefer global', which makes BIRD to use global next hop instead of link-local: https://gitlab.nic.cz/labs/bird/-/commit/8f79e6b93e32a4eb7e4dda9bd4a9d04400b79d45 > On 9/20/22, 6:11 PM, "Ondrej Zajicek" <[email protected]> wrote: > > On Mon, Sep 19, 2022 at 01:23:28PM +0000, Mazur, Dariusz via Bird-users > wrote: > > Hello, > > In my setup I have iBGP session with peer , and I learn v6 route. It is > iBGP so we have 2 next hops global and link-local. By default bird uses > link-local when route is exported to kernel. Is there any command to change > this behavior and use global v6 address as BGP next hop when we export routes > to kernel ? > > Hello > > The dual next hop for IPv6 routes is kind of hack and not really > reflected in filter code, which means that bgp_next_hop attribute > represents just global address. Therefore, you can do: > > bgp_next_hop = bgp_next_hop; > > in remote IBGP export filter to reset bgp_next_hop attribute to just > its global address. > > I think it would not work in local IBGP import filter - we assign > recursive immediate next hop based on bgp_next_hop when route is received > before import filter, so later change of bgp_next_hop in IBGP import > filter would not affect existing immediate next hop. > > You can also change immediate next hop (route attribute 'gw'), either in > local IBGP import filter, or Kernel protocol export filter: > > gw = bgp_next_hop; > > but that would work only if you have flat network and there is no > intermediate hop between local system and bgp_next_hop. > > > We probably should just add option to ignore link-local BGP next hops ... > > > > Table master6: > > fc00:2001:100:12::/64 unicast > [2001:4878:c225::1:3:2__r02.ien.labkrk01.sdn 12:57:29.076] * (100) [i] > > via 2001:4878:c225::1:3:2 on eth-1\1\4 > > Type: BGP univ > > BGP.origin: IGP > > BGP.as_path: > > BGP.next_hop: 2001:4878:c225::1:3:2 fe80::1:3:2 > > BGP.local_pref: 400 > > BGP.community: (20940,550) > > > > Thanks, > > Dariusz -- 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."
