iBGP problem with full meshed routers

[Ondrej Zajicek]

On Mon, Aug 19, 2019 at 12:11:20AM +0200, Martin Bosner wrote:
> Hello Mike,
> 
> thank you for your reply. I also thought about that but since other routers
> (e.g. router E) can exchange routes with router A (routed over other BGPs)
> i don't think that we need static routes or OSPF. Or is that assumption
> wrong?

Routes received from multihop BGP must have BGP next hops resolvable through
non-recursive routes (e.g. static, OSPF or even direct BGP). So perhaps you
have appropriate direct BGP route on E, F, but not on G, H?


If you see this on G, H:
> > 223.230.128.0/22     unreachable [routerG_to_routerA 03:15:02.410 from
> > 153.92.124.4] * (100/-) [AS45609?]
> > ...
> > BGP.next_hop: 153.92.124.4

And this on E, F:

> > 223.230.128.0/22     unicast [routerE_to_routerA 02:42:58.878 from
> > 153.92.124.4] * (100/?) [AS45609?]
> > via 192.168.0.1 on external
> > ...
> > BGP.next_hop: 153.92.124.4

You should check 'show route for 153.92.124.4' on these machines to see
the route for BGP next hop.

-- 
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."