Re: NM bug 684242 and other stuff

[Dan Williams <dcbw redhat com>]

On Wed, 2012-09-26 at 14:56 -0400, Gene Czarcinski wrote:
> On 09/26/2012 02:38 PM, Dan Williams wrote:
> > There's some example keyfiles here:
> >
> > http://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/src/settings/plugins/keyfile/tests/keyfiles
> >
> > manual IPv6 is for example:
> >
> > http://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/src/settings/plugins/keyfile/tests/keyfiles/Test_Wired_Connection_IP6
> >
> > but that doesn't describe SLAAC.  For that, you just need:
> >
> > [ipv6]
> > method=auto
> What I am looking for (without diving into the Networkmanager code any 
> more than I have too) is a keyfile configuration which will cause RA to 
> be used for the default route and dhcpv6 for the client's IPv6 address 
> and,m if dhclient is used with my mods, a ddns update.

I believe (and either Pavel or Tore correct me if I'm wrong) that would
should be:

1) Using Router Advertisements and possibly setting the prefix too
2) Setting the "Managed" flag for RA (AdvManagedFlag for radvd)
3) Setting NM to "method=auto"

This should cause the kernel to recognize your router and add a route
for it, but should not cause the kernel to use the prefix in the RA.
The Managed flag will cause NM to perform DHCPv6 for address assignment
and DNS options.  In IPv6 with SLAAC (including DHCP) the default router
is *always* determined from Router Advertisements; that's the confusing
bit for people used to IPv4.  In IPv6, the default router determination
can be *completely* separate from address assignment.

Note that if you use DHCPv6 for address assignment, you'll only ever be
able to use /64, because that's all DHCPv6 supports.  The IPv6 standards
really, really, really want you to use RA as much as possible.

> On the surface, I must say that I like keyfile a lot better than the 
> ifcfg-rh stuff.

Yeah, though at least on Fedora we're going to live with ifcfg files for
a long long time.  Since that's what admins know, and that's what users
know, and that's how the documentation (including Google search results)
are written for.  It's hard to change collective knowledge.

Dan