v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]

Nathan Ward nanog at daork.net
Sat Feb 7 07:10:12 UTC 2009

On 6/02/2009, at 1:01 PM, David W. Hankins wrote:

> On Thu, Feb 05, 2009 at 05:12:19PM -0600, Jack Bates wrote:
>> Operationally, this has been met from my experience. In fact, all  
>> of these
>> items are handled with stateless DHCPv6 in coordination with SLAAC.
>> Stateful DHCPv6 seems to be limited with some vendors, but unless  
>> they plan
>> to do proxy-nd, I'm not sure they'll gain much except for end system
>> compatibility.
> SLAAC fails in the end because you cannot predict what address the
> client will choose.
> So it fails in scenarios where enforcing network policy is important.

It works fine, you set the additional information flag, and the host  
goes to the DHCPv6 server and you can now do whatever dynamic network  
policy you want. This might break with privacy extensions, I'm not sure.

I'm a bit confused though - do you consider it to be a good idea to  
set network policy differently for multiple hosts on a single  
broadcast domain? There are some people that do that, but as Randy  
would say, it is something that I would encourage my competitors to do.

Nathan Ward

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