6to4 strangeness

Tim Chown tjc at ecs.soton.ac.uk
Tue Feb 14 20:05:07 CET 2006

On Tue, Feb 14, 2006 at 05:30:45PM +0000, bmanning at vacation.karoshi.com wrote:
> > Source address: 3FFE:2500:310:3:204:27FF:FEFE:249F
> > 
> >   1 www.osx86project.org (2002:42EB:B46B::2) 396 msec 384 msec *
> > 
> > This means that for them, or rather, their 6to4 gateway, my  
> > 2001:1af8::/32 address is unreachable, but 3ffe:2500::/32 works. WTF?
> 	I guess that "foot in the grave", zombie IPv6 network
> 	prefix 3ffe:: is -NOT- going to go quietly into that 
> 	good night.  :)  dispite administrative efforts to kill
> 	it off.  
> 	i'd recommend that you never try to reach anything using the 3ffe
> 	space ever again, since you don't want to believe its being
> 	used.

Is a valid explanation that their 6to4 relay is only 6bone-connected,
only seeing 3ffe:: space advertised from their 'native' IPv6 provider?

Thus they can't respond to 2001:: space, and your 3ffe:: prefix will
work but not your 'proper' one.

I get the same symptom by the way (unreachable) from our (only) 2001::

Have you asked them what their connectivity is? :)


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