How to generate IPv6 RA without any prefixes?

[sthaug at nethelp.no]

> > I would like to get rtadvd to send RAs completely *without* a prefix
> > info option. My Juniper routers at work can do this just fine...
> 
> Oh I see. I haven't tried this case with FreeBSD configuring RA with
> default route info only. So, how your Juniper router coordinate your
> DHCPv6 server to inform the hosts or nodes where to get prefix info
> since then your router wasn't configured with pinfoflags options?

The router sends RAs with the "managed" flag, in the RA header (not
connected to any specific prefix). This tells the clients that they
should attempt DHCPv6 configuration.

> Or
> the hosts are just configured with DHCPv6 client informing directly
> the DHCPv6 server for IPv6 address info while its default route is
> obtainable via RA through SLAAC?

The default route and the "managed" flag come from RA. The rest from
the DHCPv6 server.

Some of us would *like* DHCPv6 to be able to work without RA - but that
is a different (religious) discussion.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no