Important IPv6 Policy Issue -- Your Input Requested

Thu Nov 11 23:42:26 UTC 2004

On 11-nov-04, at 16:36, Adi Linden wrote:

> What are my options today to obtain ip address space? My requirements 
> are
> well met by a /27 subnet. ARIN won't give me a globally unique /27 for
> personal use. So the /27 comes from my service provider, which has 
> several
> caveats. I cannot multi-home. I cannot keep my address space when 
> changing
> providers. I most likely cannot keep my address space moving to a
> different city but staying with the same provider.

This is not unlike the situation in IPv6 where you will get a /48.  :-)

> About half of the devices within my on private network are statically
> defined and for local use only. They will never need global access.
> Because they are awkward to configure I do not want to renumber, ever. 
> My
> solution is to use RFC1918 address space for this network.

Use unique site locals for them in IPv6.

> NAT is my technology of choice to
> connect to the global internet, but other solutions are possible.

You were talking about devices that need no connection to the rest of 
the world. So how does NAT enter the picture?

> If I understand correctly, ipv6 will force me into using provider
> dependent globally unique address space.

For anything that needs to connect to the internet at large, yes. For 
stuff that only needs to be reachable from within your sites and people 
you work close together with, ULAs fit the bill.

> Unless my provider of the day is
> required to assign me address space that is and/or permanently assigned
> and portable it does not meet my needs. Why not? I am not willing to
> renumber when I change providers. I have no problem using NAT to obtain
> connectivity from provider B using providers A address space 
> internally.
> But that only works if provider A is prevented from reusing 'my' 
> addresses
> if I terminate my contract.

Think of it this way: provider A is called IANA. They seem to offer a 
great deal: you get to keep your address space forever, and it costs 
(next to) nothing. However, your connectivity sucks: there is none.

We'll all have to learn some new tricks with IPv6. A model that appeals 
to me is to give all hosts within a site a unique site local address, 
and everything that needs external connectivity an address from the ISP 
of the week. Then, treat all the ULAs as "internal" and all the ISP 
derived addresses as "external". This means there is no need to have 
extensive access lists that contain ISP derived addresses, as all 
access to internal resources must be done using the ULAs, which don't 
change. (When properly implemented, default address selection will make 
sure the appropriate source/destination addresses are used for 
different types of connections.)