Re: [Int-area] Revving draft-intarea-shared-addressing-issues

> -----Original Message-----
> From: Dan Wing [mailto:dwing@cisco.com]
> Sent: Monday, June 14, 2010 1:16 PM
> To: 'Bernard Aboba'; Dave Thaler; ford@isoc.org
> Cc: int-area@ietf.org; brian.e.carpenter@gmail.com; draft-ford-shared-
> addressing-issues@tools.ietf.org; lorenzo@google.com
> Subject: RE: [Int-area] Revving draft-intarea-shared-addressing-issues
> 
> 
> 
> > -----Original Message-----
> > From: Bernard Aboba [mailto:bernard_aboba@hotmail.com]
> > Sent: Monday, June 14, 2010 1:05 PM
> > To: dthaler@microsoft.com; dwing@cisco.com; ford@isoc.org
> > Cc: int-area@ietf.org; brian.e.carpenter@gmail.com;
> > draft-ford-shared-addressing-issues@tools.ietf.org; lorenzo@google.com
> > Subject: RE: [Int-area] Revving draft-intarea-shared-addressing-issues
> >
> > The NAT box can use its public IPv4 address to enable 6to4, thereby
> > providing IPv6 support for hosts "behind" it.  Why would this result
> > in a disconnected IPv6 island?
> 
> Diagram of what I understand the problem to be with 6to4 behind another NAT:
> 
>   IPv6 host--+
>               \
>                +---[home NAT]----[Carrier's NAT]---[Internet]
>               /      ^       ^                  ^
>   IPv6 host--+       ^       ^                  ^
>                      ^       ^             IP address sharing
>                      ^       ^             with multiple
>                      ^       ^             subscribers
>                      ^       ^
>                      ^     the in-home NAT's WAN address
>                      ^     is not publicly routable
>                      ^
>                      ^
>                this in-home
>              NAT turns on 6to4

The in-home NAT cannot turn on 6to4, it's simply not possible.
To turn on 6to4 per the RFC one has to have a globally unique
IPv4 address, which it doesn't in the diagram above.

-Dave

> 
> -d
> 
> > > From: dthaler@microsoft.com
> > > To: dwing@cisco.com; ford@isoc.org
> > > Date: Mon, 14 Jun 2010 19:04:31 +0000
> > > CC: int-area@ietf.org; brian.e.carpenter@gmail.com;
> > draft-ford-shared-addressing-issues@tools.ietf.org; lorenzo@google.com
> > > Subject: Re: [Int-area] Revving
> > draft-intarea-shared-addressing-issues
> > >
> > > > Some routers enable 6to4 [RFC3056] on their WAN link.
> > 6to4 requires a
> > > > publicly-routable IPv4 address. Enabling 6to4 behind a
> > NAT causes a
> > > > disconnected IPv6 island."
> > >
> > > The last sentence above is incorrect. The second sentence
> > is correct.
> > > So one cannot "enable" 6to4 behind a NAT since one has no
> > > publically-routable IPv4 address. Hence one does not get an IPv6
> > > island. One gets no IPv6 at all (from 6to4 anyway).
> > >
> > > -Dave
> > >
> > > _______________________________________________
> > > Int-area mailing list
> > > Int-area@ietf.org
> > > https://www.ietf.org/mailman/listinfo/int-area
> >
> >
> 