Subject: Teredo routing status?

From: "Anssi Porttikivi" <[email-masked]>
Date: Wed, 17 May 2006 16:09:10 +0300

I found in the Wikipedia Teredo article that
http://www.sixxs.net/tools/grh/lg/?find=2001::/32
can be used to verify that the new Teredo prefix is indeed widely
available as an anycast route. There was also a reference to this list
and a hint by David Thaler from Micorosoft that the prefix can be
configured to Windows:

	http://psg.com/lists/v6ops/v6ops.2006/msg00064.html 

Done that, and my Teredo does not work. Windows Teredo says "secondary
server address unreachable".

What is this configuration changed supposed to affect, exactly? Does the
MS Teredo server accept a client request for address with this prefix?
Is the global routing for it really working? Is Teredo reliably and
universally working with ANY configuration?

I have fond memories of those few times last year when a South Korean
public relay actually advertised the old prefix in global BGP, and
Teredo actually worked globally.

[email-masked]
skype: gatestone

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From: Jeroen Massar <[email-masked]>
Date: Wed, 17 May 2006 15:27:17 +0200

> server address unreachable".

Because you are most likely still using the old servers which only
support (afaik) the old 6bone prefix and not yet the 2001::/32 one.
Also, did you reboot? :)

> Is the global routing for it really working?

The v6 path is there, that is what GRH shows, though that still depends
on the viewpoint and if the route is actually made visible globally or
only for a limitted set of networks (eg using no-export or filters).

The v4 path is the other question and you will have to configure it to
use a server which supports the RIR prefix.

That said, you will want to contact the operator of your Teredo server
you are using, though you might some of them here, if you really want
operational people and not standards folks, try:
http://lists.cluenet.de/mailman/listinfo/ipv6-ops
Though I have to note that that is not a help-me list either.

> Is Teredo reliably and universally working with ANY configuration?

According to the people who tested it it seems to work except for the
cone-nat situation (or was it the other one, see wikipedia ;)

> Teredo actually worked globally.

Which was most likely quite useless latency wise when your packets had
to travel twice around the world; it also makes debugging a lot of
'fun'.

Greets,
 Jeroen

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From: Rémi Denis-Courmont <[email-masked]>
Date: Wed, 17 May 2006 17:27:05 +0300

Hello,

Le Mercredi 17 Mai 2006 16:09, vous avez écrit :
> What is this configuration changed supposed to affect, exactly?

It changes which prefix Windows expect from the server.

> Does the MS Teredo server accept a client request for address with
> this prefix?

Not yet, or at least not at teredo.ipv6.microsoft.com. I couldn't get 
any infos as to whether and when this is going to change.

> Is the global routing for it really working?

The IANA prefix (2001:0::/32) is working; ITGate is advertising the 
prefix and running a working relay. The experimental prefix 
(3ffe:831f::/32) is not (anymore).

> Is Teredo reliably and universally working with ANY configuration?

No. No tunneling system works universally anyway, with the possible 
exception of DNS tunneling. Now, if you mean any NAT configuration, 
assuming there is no firewalling problems as well, then, no, Teredo as 
it is specified does not support symmetric NATs.

There are undocumented-unspecified extensions in Windows Vista that 
would allow traversal of any NAT, provided either side of the packets 
exchange is behind no NAT or a friendly NAT. This would imply NAT 
traversal would at least work properly toward the whole IPv6 Internet 
(because Teredo relays are *NEVER* behind unfriendly NATs), and toward 
most Teredo clients behind SOHO NAT routers.

Unfortunately, given this is not a specified extension, and that I'm 
fairly confident it's in explicit contradiction with the current 
specification, I have some reservations as to whether it's actually 
going to work as advertised. That is to say, if Teredo relays are 
running Vista, it might work fine, but not otherwise. I'd be happy to 
provide support for this in my own implementation, but I can't do so 
with zero concrete information.

Also, the guys behind the NICI-Teredo implementation have seemingly 
developped their own extensions that, I assume, would allow Teredo to 
work in all cases. But their results is yet to be released:

“Huang, S.-M., Wu, Q.-C., and Lin, Y.-B. Enhancing Teredo IPv6 Tunneling 
to Traverse the Symmetric NAT, Accepted and to appear in IEEE 
Communications Letters.” (quoted from http://liny.csie.nctu.edu.tw/)

Regards,

-- 
Rémi Denis-Courmont
http://www.simphalempin.com/home/

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From: "haofeng Zhang" <[email-masked]>
Date: Thu, 18 May 2006 13:41:27 +0800

Hi,

I did the same thing and got the same result.
The default teredo server spicified in Windows XP is
teredo.ipv6.microsoft.com. So even we have changed the teredo prefix in
teredo client, we can never change the prefix advertised by MS teredo
server.
I think it's why teredo service doesn't work.

Also, current implementation of teredo service in MS doesn't work reliably
and universally without ANY configuration. Accoriding to the document of
Windows Vista, it supports teredo service transparent to ANY kinds of NATs.

PS, it's good to see many operators are advertising 2001::/32 teredo prefix
to global BGP table.

Zhang Haofeng
MSN: [email-masked]
2006-5-18

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From: Rémi Denis-Courmont <[email-masked]>
Date: Thu, 18 May 2006 17:23:51 +0300

Le Jeudi 18 Mai 2006 16:42, vous avez écrit :
> Who is announcing it besides 12779?

At large, nobody indeed.

> I will add Teredo server/relay
> support to our 6to4 relay and announce 2001::/32 as soon as
> I get an implementation working on FreeBSD 5.4.

FYI, ng_teredo might work, though it's not clear to me whether it's been 
totally ported to FreeBSD 5. Miredo is supposed to work.

Regards,

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From: Kevin Loch <[email-masked]>
Date: Thu, 18 May 2006 09:42:04 -0400

haofeng Zhang wrote:
> PS, it's good to see many operators are advertising 2001::/32 teredo 
> prefix to global BGP table.

Who is announcing it besides 12779?  I will add Teredo server/relay 
support to our 6to4 relay and announce 2001::/32 as soon as
I get an implementation working on FreeBSD 5.4.

- Kevin