Microsoft and Teredo

Thu May 31 12:56:04 UTC 2007

Hi Sean,

Most of the access providers, can't quickly move to dual-stack. It may be a
problem of existing equipment or even L2 technology (as the cable/DOCSIS 2.0

The bigger issue is upgrading the CPEs. Lack of plans in the last years,
didn't helped the low cost vendors to deliver them with dual-stack. Yes,
there are open source alternatives, but they don't work so easily for all,
as not all the users are able to do that upgrade, and otherwise it may mean
a hard support cost. Obviously this will be challenged by those ISPs that
want to start providing new services based on IPv6 (surveillance, home
automation, IPTV, etc.).

So having a CPE typically means either the user has a single PC and the CPE
may be configured as bridge and then the user PC has the public IPv4 address
(case for 6to4), or the user PCs are behind NAT (caser for Teredo).

The alternative will be softwires (L2TP), but is not yet fully supported
(I'm not even sure if Vista support it form Microsoft, for XP I think not

So providing a combination of 6to4 relay and Teredo server+relay, is a
simple way to offer IPv6 connectivity at a very low cost and improve
performance vs. using relays somewhere else.

Of course, this will be more obvious as more applications use IPv6, and in
fact, my suggestion will be, once we have some more relays across all
Internet, that XP and Vista get one of those updated changing the setup of
the address selection table, so Teredo and 6to4 become preferred to IPv4 :-)

In fact, it will be quite easy to, at boot time, do a quick test (ICMPv6 +
ICMPv4) of the "availability" of a good relay, to decide if the policy table
prefers by default Teredo/6to4 instead of IPv4.

Of course all this is assuming that you can't provide native IPv6 !

Also one very important issue will be to make sure that Windows 2003 (which
runs lots of websites with IIS), is updated with Teredo Server/Relay
function or at least that Teredo host-specific relay functionality works by


PS: What it will be good is to get at least some of the MS servers
dual-stacked :-) and you know, if help is needed, I don't mind to spare some
time for that !

> De: Sean Siler <Sean.Siler at>
> Responder a: <owner-nanog at>
> Fecha: Thu, 31 May 2007 04:27:53 -0700
> Para: Nathan Ward <nanog at>, Nanog <nanog at>
> Conversación: Microsoft and Teredo
> Asunto: RE: Microsoft and Teredo
> Nathan,
> While these are really good questions, I'm afraid I don't have really good
> answers to them yet.  We haven't made the bits available for customers to
> install their own Teredo Servers/Relays at this point, and because we haven't,
> we also don't have good deployment guidance to go along with that.
> I have my own feelings, but let me ask this: what do you all feel about
> installing a Teredo server in order to provide v6 connectivity to your
> clients? Is this something that you are really interested in?
> You feedback is welcome.
> Sean Siler|IPv6 Program Manager|Microsoft
> sean.siler at | 703.485.1170
> IPv6 is ready. Are you?
> -----Original Message-----
> From: owner-nanog at [mailto:owner-nanog at] On Behalf Of Nathan
> Ward
> Sent: Wednesday, May 30, 2007 6:44 PM
> To: Nanog
> Subject: Re: Microsoft and Teredo
> On 31/05/2007, at 5:40 AM, Sean Siler wrote:
>> I understand some questions recently arose regarding Microsoft and
>> Teredo. I tried reading through the archives but it has more twists
>> that Pacific Coast Highway.
>> Are there some specific requests/questions that I can help with?
> Probably, yeah.
>  From another post my Michael Dillon:
>> Since we are all collectively playing catchup at this point, it
>> would be
>> very useful for some clear guidance on who needs to deploy Teredo and
>> 6to4 and where it needs to be deployed. Also, the benefits of
>> deployment
>> versus the problems caused by not having it. Should this be in
>> every PoP
>> or just somewhere on your network? Are there things that can be
>> measured
>> to tell you whether or not lack of Teredo/6to4 is causing user
>> problems?
> Maybe you can provide operational experience from running the Teredo
> servers and relays that Microsoft host? Do you host them just at
> Microsoft or do you also have some inside ISPs? Have you done any
> work to help/advise on deploying Teredo servers/relays in to ISPs?
> Any learnings from that that you can share? What about corporate
> networks?
> That oughta get you started :-)
> --
> Nathan Ward

The IPv6 Portal:

Bye 6Bone. Hi, IPv6 !

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