[OpenIndiana-discuss] DHCPv6-PD

[Gary Gendel]

On 7/27/12 11:02 AM, James Carlson wrote:
> Gary Gendel wrote:
>> Does OpenIndiana support this protocol?  If so, does anyone have a basic
>> howto written that will step me though setting up my OI server to do
>> IPV6 routing via Comcast.  So far, I have only been able to get a single
>> /128 address, but with DHCPv6-PD it should get a /64 address.  Thanks.
> I know that when I wrote the code, I didn't add support for RFC 3633
> Prefix Delegation.  It wasn't part of the customer request Sun received
> that started the project.
>
> I don't know if anyone's added it since, but I doubt it.  I think it's
> unlikely to be useful unless there's also a DHCPv6 server component that
> can read the delegated prefixes and do something intelligent with them,
> but last I checked, OI doesn't have a DHCPv6 server.
>
> For what it's worth, Prefix Delegation has nothing to do with the
> configuration of the on-link addresses.  If you're seeing a /128 where
> you expect a /64, the problem is that you're not getting a proper IPv6
> Router Advertisement for that prefix.
>
> DHCPv6 works in a rather different manner from IPv4 DHCP.  In
> particular, DHCPv6 *DOES NOT* include the prefix information in the
> assigned address data.  Instead, the DHCPv6 client is expected to get
> the prefix information using the standard Router Discovery mechanism
> that's always used in IPv6 to get prefixes from IPv6 routers.
>
> Seeing /128 means that something in that fundamental mechanism has
> broken down.  Either in.ndpd has been somehow disabled or the upstream
> router is not providing complete information.
>
It's the latter.  From my conversation with Comcast:

For ipv6 to work natively with Comcast you need DHCPv6-PD in your 
router. Then Comcast will assign you a /64 prefix. If you plug in a 
computer directly they'll assign you a single ipv6 address. Native ipv6 
won't work any other way.

Gary