Teredo source addresses from 6to4 relay

[Mohacsi Janos]

On Wed, 16 May 2007, David Malone wrote:

> On Fri, May 11, 2007 at 11:44:47AM +0200, Remi Denis-Courmont wrote:
>> What you would need there is source routing. Better yet understand why
>> RFC3484 is not applied properly...
>
> Well, FreeBSD 4 behaved (roughly) as if it had RFC 3484 but with
> an empty policy table. Later versions of FreeBSD have a configurable
> table and by default you should get the table suggested in RFC 3484.
> OTOH, until quite recently vinilla Linux kernels just picked the
> first IPv6 address of the right scope on the outgoing interface. I
> think the situation is a bit better now.

And also the glibc starts supporting proper RFC 3484 policy table. Fedora 
Core 6 has some support for it, but there is some problem. 
I also tested Fedora Core 7 live CD: glibc version 2.5.90 release 21 and 
it seems to be working properly. I think this a good way to go forward, 
however it will take time (~ 1 year or so) to new glibc would be adopted 
in all the Linux distribution.
http://ipv6.niif.hu/m/IPv6hostslinux_disableIPv6

>
> The default policy has no mention of Teredo. I wonder what the
> pros and cons of adding an entry for 2000:0000::/32 to treat Teredo
> in a similar way to 6to4 would be?

I think a resonable Teredo policy should be put on all RFC3484 compliant 
implementation. I think Teredo should be used only as a last resort IPv6 
connectivity solution. Maybe administrators can increase the preference if 
a teredo relay is operated locally and it is the prefered to go to IPv6 
internet via Teredo.

Regards,
 		Janos Mohacsi