Inject ethernet-based defaults to OSPF

[Ondrej Zajicek]

On Wed, Sep 18, 2019 at 11:53:30AM +0200, daniele wrote:
> Hello list,
> I???m looking for some advice from someone that has more experience. I'm
> running bird 1.6.6.
> I have two routers R1 and R2, each with a single internet uplink U1 and U2,
> running OSPF and sharing a LAN ethernet segment. Both U1 and U2 are
> dhcp-based ethernet segments themselves with a next-hop IP address that can
> change. I want R1 to be the primary LAN internet gateway and R2 the
> secondary. Should U1 fail, R1 has to route to R2 in order to reach internet
> through U2.
> How would you recommend to inject U1 and U2 default routes into OSPF? I
> cannot use the next-hop ip address as it changes along time, and an
> interface-based static route would not work.

Hello

I would suggest learn default route using kernel protocol (allow in
import, option 'learn'). Then set ospf_metric2 in OSPF export filter
(different on R1 and on R2).

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."