OSPF for IPv4 over IPv6 only?

[Sebastian Hahn]

Hi Nico,

> On 30. Jan 2024, at 10:32, Nico Schottelius via Bird-users <bird-users at network.cz> wrote:
> OSPFv3 works fine on IPv6 and when creating two instances, one for IPv6
> one for IPv4, things look correct. But how does OSFPv3 conceptually work
> if the interface of the ospf area do not have IPv4 addresses themselves?
> 
> In the BGP case we can use "extended next hop on;" to use the IPv6
> nexthop for IPv4, but I did not find a similar setting for OSPF to
> accept IPv6 nexthops for IGP IPv4 addresses.
> 
> Is there a way to purely go IPv6 only and still relay stub network IPv4
> information via an IPv6 only internal area?

I was facing the same issue before, and unfortunately, RFC 5838
explicitly forbids IPv4 over IPv6 for OSPF.

As an alternative suggestion, I have since evaluated babel which mostly
suits my purposes (except for some features not yet implemented in bird,
like strict bind) - but maybe it works for you?

Cheers
Sebastian