IPv6 Confusion

Nathan Ward nanog at daork.net
Wed Feb 18 20:23:59 UTC 2009

On 19/02/2009, at 9:08 AM, Chuck Anderson wrote:

> On Wed, Feb 18, 2009 at 12:55:19PM -0700, Aria Stewart wrote:
>>> On 18/02/2009 19:39, Kevin Loch wrote:
>>>> Just how DO we get the message to the IETF that we need all the
>>>> tools we
>>>> have in v4 (DHCP, VRRP, etc) to work with RA turned off?
>> What operational reasons are there for working with RA turned off?
> I don't want any system to be able to get IPv6 addressing information
> until the system has been identified in our central management system.
> I also want the IPv6 address assignment to be made centrally.

You must have missed my post asking people to be clear in their  
distinction between RA and SLAAC.

I will re-cap:
- RA does NOT give your host IPv6 addressing information.
- SLAAC gives your host IPv6 addressing information. SLAAC data is  
carried in RA messages, as an OPTION.
- Another RA OPTION is "use DHCPv6 to get addressing information".

DHCPv6 can operate without RA now. You can send DHCPv6 requests to  
your local LAN before you get an RA message telling you to do so. This  
requires you to manually configure your host to do that. That sounds  
like a waste of time, when you can use RA messages to tell your hosts  
to use DHCPv6 to get addressing information. Of course, you DHCPv6  
does not currently have an option for default router, so your need RA  
for that. Again, RA is not giving out addressing information, only  
"Hi, I am a router".

I suspect this removes the desire for getting "VRRP" without RA as  
well for those of you wanting to use DHCPv6 for addressing - RA is not  
giving out addressing information, and is only giving out "Use DHCPv6"  
bits and a router address.

Nathan Ward

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