[Dnsmasq-discuss] Using IPv6 DHCP

[Gene Czarcinski]

On 09/25/2012 05:41 AM, Sean Boran wrote:
> I also disable "enable-ra", since ra should not be needed, when using dhcp?
OK, I am going to break into the middle of this thread.

The stuff about not needing RA is not necessarily true.  I have been 
doing a little work to enhance the Linux NetworkManager package to 
support dynamic dns updates [NM uses "dhclient -6" on the client side] 
and I have submitted a patch which is in the process of being 
integrated.  In the process I have learned a number of things.

First of all, although you can currently specify that "dhcp" should be 
used for IPv6, this is wrong, does not really work, and is likely to be 
removed real soon.  Specifying "dhcp" for IPv4 works because, for IPv4, 
route information is returned.  This is not the case for IPv6 and there 
will be no default route which makes things more than a little 
difficult.  The "correct" way is to specify "auto" which causes NM to 
use dhcpv6 for stateful address assignment and, with my patch, dynamic 
dns updating.  It then uses RA to provide the default route.  Currently, 
the RA is supplied by radvd.  I have tested this with both 
radvd/named/dhcpd/dhcpd6 and radvd/dnsmasq.

Of importance, here is the configuration for radvd:
> interface eth0 {
>      AdvSendAdvert on;
>      AdvManagedFlag on;
>      prefix 2001:db8:1:2::/64 {
>          AdvAutonomous off;
>      };
> };
and you might want to read: 
https://fedoraproject.org/wiki/Tools/NetworkManager/IPv6

I have not tested dnsmasq to see if it could provide the RA, dhcp, and 
dns services for IPv6 but I am interested that it would.

I am also interested in what works with other clients and specifically 
Windows clients.

Gene