INET6 -- and why I don't use it

Kevin Oberman oberman at
Sun Mar 9 23:41:56 UTC 2008

> From: JoaoBR <joao at>
> Date: Thu, 6 Mar 2008 20:19:33 -0300
> On Thursday 06 March 2008 16:24:08 Kevin Oberman wrote:
> > > Agreed.  But at this stage I can't justify the effort to do anything
> > > more than have a very cursory glance it at.  What benefit would I
> > > derive from setting up an IPv6 network and attempting to experiment
> > > with it?  My ISP won't support IPv6 and I'm reasonably certain my
> > > cable-modem doesn't either so IPv6 connectivity would entail some
> > > sort of tunnel.
> >
> > You don't set up an IPv6 network. You simply have end nodes that will
> > use IPv6 when/if it is available by just making a one-line change in
> > rc.conf as opposed to a kernel re-build.
> >
> > If you have a Windows Vista box (and I'm told several people do, even
> > though I have never used one), it has IPv6, it is always enabled, and it
> > REALLY, REALLY tries to use it using several mechanisms including Toredo
> > tunnels (which are either very cool or the spawn of Satan, depending on
> > who you talk to).
> eventually this few lines show why this thread goes so far ... 
> your computer will or better CAN use ipv6 when it is on a ipv6 network and 
> nothing else, ipv6 WILL NOT come eventually available on your ipv4 network 
> (unless it's address space change ...)

I'm unclear on the last sentence. I can assure you that IPv6 WILL come
to your IPv4 network. It's not 'if' but 'when'. I am regularly amazed to
see the number of people who bury their heads in the sand and claim it

> this has nothing to do with vista or dawn, this is a routing issue and
> as long as you are NOT on a ipv6 network you do NOT need ipv6 on our
> machine, still beeing able to access ipv6 networks ... as weel as ipv6
> networls can access ipv4 networlks guys, if not so all this ipv[4|6]
> stuff wouldn't make any sense ...

Whether you need to or not, you WILL have it if you run Vista. Read up
on Teredo tunnels. You can turn this off on Vista, but it is on by
default and every Vista system not configured to turn it off WILL run
IPv6 regardless of what network it is connected to. 

Whether you need IPv6 is debatable. If you want to see the Kame dancing
turtle, you will need IPv6. There are a very few specialized locations
that are IPv6-only, but they are of little or no general interest. None
the less, if you have Vista up and running or FreeBSD with the
appropriate setup (6to4), your can reach them even if your network
connection is IPv4 only.

I'm afraid I couldn't parse the latter part of this paragraph. (Still,
your English is far better than my Portuguese.)

> as long as you talk in endpoints you also can access any rfc1918 address as 
> long as you have some setup (VPN?) for that, so what you say here is not 
> exactly true, either for windows nor for unix, the OS at the end has 
> absolutelty NOTHING to do with ipv6 neither with ipv4 ...
> so final point here is that you need ipv6 on your machine when you are
> on a ipv6 network or want by any means connect directly to a remote
> ipv6 endpoint, similare as you do a VPN connection to a rfc1918
> network wether this are tunnels or whatever provided by either satans
> or daemons ...

Please learn a bit about IPv6 and modern implementations of tunnels
before making assertions about how networks have to work.

FWIW, I run a full production IPv6 network and have been working with
IPv6 since it was still being developed by the IETF.  It's far from
perfect and, in fact, I am quite disappointed on how it came out, but it
is what it is and, as of today, it is the only game in town that can
move us to beyond the end of IPv4 address space availability. Live with
it or live in the expensive past. (IPv4 addresses will soon get
very expensive as the supply runs out.)
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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