[6bone] Network Address translation question

[Mohacsi Janos]

On Wed, 22 Jun 2005, Stig Venaas wrote:

> On Mon, Jun 13, 2005 at 02:18:27PM +0200, Mohacsi Janos wrote:
>>
>>
>>
>>
>> On Mon, 13 Jun 2005, Iljitsch van Beijnum wrote:
>>
>>> On 13-jun-2005, at 11:09, Tim Chown wrote:
>>>
>>>> With IPv6, you can run ULAs and globals side by side, if you wish, though
>>>> this hasn't exactly been widely tested as yet, as far as I'm aware.
>>>
>>> The trouble is that there is no clear way to force the use of internal
>>> addresses for internal stuff and external addresses for external stuff.
>>
>>
>> This is easier, if you setup RFC3484 style address selection. You give
>> higher priority to your local addresses.
>
> I also think that for multicast you would by default end up using
> longest matching prefix (rule 8 in 3484) which leads to ULA being
> preferred to other global addresses. And due to RPF the multicast
> packets would never leave the site.
>

Ooops this can be a problem.

> One should probably also define labels so that ULA is used as
> source for multicast scope <= 5 or <= 8 while global for others. Or
> simply never use ULA as source for multicast.

The 5 or 8 seems to be artifical... More general solutions would be 
nice...

>
> I'm wondering a bit how many systems support full 3484 allowing you
> to modify the policy table. Another issue is how a manager can
> configure this on hosts. One option is DHCP as proposed in
> draft-fujisaki-dhc-addr-select-opt-00.txt

I think pretty large number of hosts potentially can support RFC3484.
Windows XP/2003 fully supports it. All *BSD systems also fully supports 
it. There is some kind of preliminary support in Linux....

I was thinking of having something similar - I will look at the 
draft of fujisaki.

Regards,
 	Janos Mohacsi