IPv6 mistakes, was: Re: Looking for an IPv6 naysayer...

Matthew Kaufman matthew at matthew.at
Thu Feb 10 10:43:50 CST 2011


On 2/9/2011 9:15 PM, Ricky Beam wrote:
> On Wed, 09 Feb 2011 16:42:14 -0500, Nathan Eisenberg 
> <nathan at atlasnetworks.us> wrote:
>> What do you mean, lit up?  You mean they're not in the routing tables 
>> that you get from your carriers?  I'd argue that's no indication of 
>> whether they're in use or not.
>
> That's pretty much the definition of "in use".  If they don't appear 
> in the global routing table, then they aren't being used.

There is no one universal "global routing table". They probably appear 
in someone's routing table, somewhere... just not yours.

If Cogent stops peering with you (I picked them, because that's not out 
of the question) and you stop seeing all their downstream routes, did 
those addresses suddenly become available for reassignment?

> I cannot send traffic to them; they cannot send traffic to me.

That's true of almost all addresses these days, what with firewalls and all.
>
> In my recent probe of route servers, I found 22 legacy /8's that were 
> partly or completely unused.  I'm a little surprised ARIN/ICANN thinks 
> it's a waste of time to even try to reclaim them.

How many days do you think a single /8 lasts at current assignment rates?

How would ARIN/ICANN go about reclaiming addresses that someone believes 
they are using but that you don't think are in use?

Matthew Kaufman





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