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

Joe Abley jabley at hopcount.ca
Thu Feb 5 22:18:15 UTC 2009

On 5-Feb-2009, at 13:44, Ricky Beam wrote:

> This is the exact same bull**** as the /8 allocations in the early  
> days of IPv4.

There are only 256 /8s in IPv4.

There are 72,057,594,037,927,936 /56s in IPv6. If you object to where  
you think this is going, then perhaps it's more palatable to consider  
the 4,294,967,296 /32s in IPv6.

[Feel free to adjust the ratios by orders of magnitude to accommodate  
the details that I am blandly ignoring above. It's doesn't change the  

So in fact it's not *exactly* the same.

Note that I am not denying the faint aroma of defecation in the air,  
nor the ghost of address assignment policies past. Also, your  
excitement is strangely invigorating.

> [...]
> Exhibit A: With IPv6 Address Autoconfiguration (tm) (patent  
> pending), you don't need DHCP. *face plant*  The IPv4 mistake you've  
> NOT learned from here is "rarp".  DCHP does far more than tell a  
> host was address it should use. (yes, I've called for the IPng WG  
> member's execution, reanimation, and re-execution, several times.)

You might like to review the DHCPv6 specification and try some of its  

There are surely simpler approaches for host configuration than the  
current mess, and it's surely true that the design process reached  
some odd conclusions on occasion, but the fact remains that the tools  
and protocols needed to get the job done in this regard do actually  
exist. It's certainly an option today to build and deploy rather than  
to bicker and complain.


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