Avoiding routes being tagged as 'unreachable' when building a route-server / lg

[Ondrej Zajicek]

On Sat, Jul 25, 2015 at 08:49:37PM +0900, Paul S. wrote:
> Hi guys,
> 
> New BIRD user here, I'm trying to use bird to build a looking glass / route
> collector.
> 
> All my core routers (I don't have a backbone network, so they run
> separately) are forwarding the full table by treating the bird system as a
> rr client. So far, this part of it works fine.
> 
> The sessions are IBGP (and multihop by nature). My problem is the fact that
> bird classifies the routes as unreachable (as they indeed are, but I don't
> intend to use them to forward) and mentions this in the birdc lookups.
> 
> A sample is given at the bottom, as well as the very simple config that I'm
> using right now (No tables, but I intend to set up tables per peer
> ('location') later)
> 
> My question is how should I deal with this issue?

Hello

I don't really understand what is the problem - if you want it just as
lookup, then you don't need to care about the next hop and the unreachable
next hop is as good as any regular next hop.

If you want to see bgp_next_hop attribute, than it is in the list of
attributes with other BGP attributes.

You can force some arbitrary next hop in BGP import filter (e.g. import
filter { gw = 10.1.1.1; accept; }', but the address have to be a direct
neighbor, therefore 'gw = bgp_next_hop' does not work if bgp_next_hop
itself is not a directly reachable IP.

You could also add some static or direct routes to have received
bgp_next_hops resolved.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at 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."
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