Thank you all for your replies, > Thinking about it, it makes sense to have something like direct mode that works with unnumbered interfaces (or ones with /32 address).
We also think that's would be very useful, either transparently to the user (depending on next hop resolution, eBGP/iBGP, IP's subnet mask) or through the addition of an explicit "direct" keyword. What would be the process to turn this thread into a feature request ? And would the Bird maintainers be interested in implementing it ? Thanks again ! On Mon, Apr 15, 2024 at 4:25 PM Ondrej Zajicek <santi...@crfreenet.org> wrote: > On Mon, Apr 15, 2024 at 12:10:05PM +0200, Daniel Gröber wrote: > > Hi Arzhel, > > > > On Fri, Apr 12, 2024 at 11:57:38AM +0200, Arzhel Younsi wrote: > > > But for IPv6, it's cleaner to only require the router's link local > address: > > > testvm2006:~$ ip -6 addr > > > inet6 2620:0:860:140:10:192:24:4/128 scope global > > > testvm2006:~$ ip -6 route > > > default via fe80::2022:22ff:fe22:2201 dev ens13 metric 1024 pref medium > > > > > > In Bird: > > > neighbor fe80::2022:22ff:fe22:2201%ens13 external; > > > > > > But then the link local address doesn't work with multihop (for obvious > > > reason). > > > bird: /etc/bird/bird.conf:22:1 Multihop BGP cannot be used with > link-local > > > addresses > > > > I use lladdrs for BGP endpoints in my network and that works fine. I > think > > using `direct` instead of `multihop` in the v6-lladdr case would make it > > work for you. > > > > One word of advice: don't use the %scope syntax, use the `interface` > > directive instead. I don't recall exactly why but I had some subtle > problem > > with that. > > > > As for your v4/32 problem, give `multihop 1` a try. That enforces no > > routers on the path to the peer like direct but allows off-subnet > > endpoints. Do keep in mind the docs recommend setting the source address > > explicitly when enabling multihop. > > Hi > > Note that using multihop fixes the issue with waiting for the address > range to appear, but there is still an issue with next hop resolution. > Multihop routes use recursive next hop resolution and in the case of /32 > address ranges, there is no route for resolving neighbor IP announced as > next hop. > > One would need a static route like: > > route NBR-IP/32 via "IFACE"; > > So the next hop will be resolved. > > > Thinking about it, it makes sense to have something like direct mode that > works with unnumbered interfaces (or ones with /32 address). > > -- > Elen sila lumenn' omentielvo > > Ondrej 'Santiago' Zajicek (email: santi...@crfreenet.org) > "To err is human -- to blame it on a computer is even more so." > -- Arzhel
