Re: Interface routes and multiple fibs

On Tue, Oct 18, 2022 at 5:12 PM Dan Mahoney <freebsd@gushi.org> wrote:

> All,
>
> Maybe a question for the -net or -rc people.  If I should ask there, let
> me know.
>
> I'm running with multiple fibs.  One fib is just box management, ssh,
> etc.  The other fib (which takes BGP routes from peers via BIRD) does DNS
> anycast things.  The DNS server runs in fib 1.  Our default route is added
> to both fibs.
>
> My fib0 routing table looks like this:
>
> Internet:
> Destination        Gateway            Flags     Netif Expire
> default            192.159.249.233    UGS        bge0
> 127.0.0.1          link#5             UH          lo0
> 182.159.249.232/29 link#1             U          bge0
> 182.159.249.236    link#1             UHS         lo0
>
> Fib 1 is missing that final route.:
>
> default            182.159.249.233    UGS        bge0
> 127.0.0.1          link#5             UH          lo0
> 182.159.249.232/29 link#1             U          bge0
>
> I've noticed that when I try to do a query (with dig) against it from fib
> 0, it sends over lo0 to the named process, but the reply packet just gets
> sent out ON BGE0, and is never received, since dig is listening on the
> interface it sent the packet over (lo0) to hear the response, which, near
> as I can tell with tcpdump -i bge0, just goes out on the wire
>
> Obviously, we can add the static route to that second fib with:  route add
> -host 182.159.249.236 -interface lo0 -fib 1.
>
> Yes, we can also make this stick useing default_routes in rc.conf.
>
> But it feels like we shouldn't have to.  This feels like a glitch, and
> that if all fibs get the SUBNET route , they should also get the loopback.
>
> -Dan
>


Why would you not expect to add a route for it?
The same subnets can exist in different fibs and be part of different lan
segments a la vlans.  Routes are required.

Perhaps I'm just confused at your confusion.

Thanks,
Paul Procacci
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