Re: NetworkManager with multiple RA (radvd failover)

[Tore Anderson <tore fud no>]

* Anders Blomdell

> Will look into VRRP, but 4.1 from http://tools.ietf.org/html/rfc579 makes me
> suspicious:
>
>    In the IPv6 case (that is, IPvX is IPv6 everywhere in the figure),
>    each router has a link-local IPv6 address on the LAN interface (Rtr1
>    is assigned IPv6 Link-Local A and Rtr2 is assigned IPv6 Link-
>    Local B), and each host learns a default route from Router
>    Advertisements through one of the routers (in this example, they all
>    use Rtr1's IPv6 Link-Local A).
>
> won't NetworkManager pick up those routes as well, and [still] mess up routing?

Well, with VRRP, only the master router will send out Router
Advertisements for the virtual router. The backup(s) will not. See RFC
5798 section 6.4.2 (325), 6.4.3 (630), and 8.2.3.

So from the hosts' point of view, only one default router exists. Even
the MAC address is a virtual one that fails over, so they don't even
have to go through NUD.

I know this works very well with Juniper's VRRPv3 implementation, at
least. I'm not aware of any open-source VRRPv3 implementation for Linux,
I'm afraid.

> Would [nm-policy.c: update_ip6_routing] be a good starting-point for looking
> into this?

I don't really know, since I'm not really a NM hacker. My role here is
to bitch and moan about all things IPv6 in the hopes that the actual NM
hackers try to shut me up once in a while by actually implementing what
I'm bitching about. ;-)

Tore