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

Mark Andrews Mark_Andrews at isc.org
Thu Feb 5 01:32:33 UTC 2009

In message <498A3CA5.6060801 at internode.com.au>, Matthew Moyle-Croft writes:
> Anthony Roberts wrote:
> > On Thu, 05 Feb 2009 11:08:44 +1030, Matthew Moyle-Croft
> > <mmc at internode.com.au> wrote:
> >   
> >> Let's face it - the current v6 assignment rules are to solve a 1990s set 
> >> of problems.  A /64 isn't needed now that we have DHCP(v6).
> >>     
> >
> > It's needed to prevent people from NATing in v6, as they'll still want
> > their stuff behind a firewall, and some of them will want subnets.
> >   
> Why do we want to prevent people using NAT?   If people choose to use 
> NAT, then I have no issue with that. 
> This anti-NAT zealotism is tiring and misplaced. 

	NAT's break lots of things and increase the development
	costs of every piece of network based software being written.

	If we could get a true accounting of the extra cost imposed
	by NAT's I would say it would be in the trillions of dollars.

	NAT's are a necessary evil in IPv4.  If every node that
	currently communicates to something the other side of a NAT
	was to have a global address then we would have already run
	out of IPv4 addresses.

	NAT's are not a necessary evil in IPv6.  Just stop being
	scared to renumber.  Addresses are not forever and when you
	design for that renumbering get easier and easier.

	For everything else there are alternate solutions.

> >> Setting the idea in people's heads that a /64 IS going to be their own 
> >> statically is insane and will blow out provider's own routing tables 
> >> more than is rational.
> >>     
> >
> > No larger than their ARP tables are now.
> >   
> And ARP tables are propogated around networks?   No, they're local to a 
> router.  
> -- 
> Matthew Moyle-Croft - Internode/Agile - Networks
> Level 4, 150 Grenfell Street, Adelaide, SA 5000 Australia
> Email: mmc at internode.com.au  Web: http://www.on.net
> Direct: +61-8-8228-2909		    Mobile: +61-419-900-366
> Reception: +61-8-8228-2999          Fax: +61-8-8235-6909
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org

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