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

Ricky Beam jfbeam at gmail.com
Fri Feb 6 00:15:04 UTC 2009

On Thu, 05 Feb 2009 17:42:27 -0500, Iljitsch van Beijnum  
<iljitsch at muada.com> wrote:
>> I've lived quite productively behind a single IPv4 address for nearly  
>> 15 years.
> So you were already doing NAT in 1994? Then you were ahead of the curve.

"NAT" didn't exist in '94.  But, Yes.  And, Yes.  I had several computers  
networked behind one with a dialup (PPP) connection.  And, as you'd  
expect, it was messy.

>> I've run 1000 user networks that only used one IPv4 address for all of  
>> them.
> But how is that relevant for the discussion at hand? Is your point that  
> if 1000 users can share an IPv4 address, 1000 users should share an IPv6  
> address?

The point is... even large enterprises don't *need* 18 billion, billion  
addresses to get anything done.

I see IPv6 address space being carved out in huge chunks for reasons that  
equate to little more than because the total space is "inexhaustable".   
This is the exact same type of mis-management that plagues us from IPv4's  
early allocations.

> Now of course that seems wasteful, ...
> and you get to generate an address from a prefix through a function that  
> gives you the same address without requiring anyone to remember that  
> address, which is also useful.

Well, it is extremely wasteful.  If you want the machine to always have  
the same address, either enter it manually or set your DHCP server to  
always give it the same address.  We do that already with IPv4.  Why do we  
need to waste so much space with such a sparse address plan?  We don't.   
But since IPv6 is H.U.G.E., "might as well."

And face reality, many people have enough trouble remembering IPv4  
addresses -- even when it's simplified to a /24 prefix plus 3 digit  
number.  They will have an even harder time remembering a 48bit or 64bit  
MAC.  Do you remember the MAC addresses of ANY of the NICs on your lan(s)?

>> This is the exact same bull**** as the /8 allocations in the early days  
>> of IPv4.
> Oh no. ...

Yes. It. Is.  We have this incomprehensibly huge address space that we  
cannot possibly, EVER, use up, so let's divide it on ridiculously huge  

>> The idea of the "connected home" is still nowhere near *that* connected;
> It took us 15 years to get this far with IPv6. There is no IPv7 on the  
> horizon currently, so even if we start that tomorrow we'll have to get  
> by with IPv6 (and IPv4...) until about 2024. I'm pretty sure we'll be  
> *that* connected by that time.

I'm not.  I'll be very surprised if IPv6 has been universally adopted by  
then.  I'm not sure we'll be completely out of IPv4 space by then.

> IPv6 changes too much but it doesn't fix enough.

It's not even that.  Had they simply not ignored, and out-right dismissed  
as "wrong", the way networks were being run, then we wouldn't have the  
mess we have today.  I pick on autoconfig because it's the simplest bit of  
stupid on their part... we have Stateless Autoconfiguration, *jedi hand  
wave*, you don't need DHCP.  It was bull the instant they said it.

You don't use DHCP.  Well, good for you.  There are hunreds of thousands  
of people who do.  We appreciate you telling us we don't need the  
technology we need.

(It's the "I don't use it so nobody else needs to, either" attitude that  
has given us a whole bunch of things to re-invent for IPv6.)


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