6to4 borkeness (Was: Google and IPv6)

[Kevin Day]

On Mar 19, 2008, at 11:26 AM, Tim wrote:

>
>> FWIW, my experience with 6to4 is more positive than Jeroen's. It
>> works almost all the time for me, except when someone breaks the
>> 2.0.0.2.ip6.arpa zone, but that hasn't happened for months. Mind
>> you, many of the ISPs that I regurally use have their own relays
>> or a relay close by.
>>
>> For me, debugging 6to4 hasn't proved that much harder than anything
>> else. You can find the relay at your end by tracerouting to
>> 192.88.99.1.  It's true that the reverse path is hard to debug, but
>> that's the same no matter what you're using. It was a little easier
>> in IPv6 when we had RH0 (though I know Jeroen prefers looking glasses
>> for this sort of thing).
>
> Ok, so I've noticed that I'm not able to reach hinet.net at all,  
> pretty
> consistently.  It's possible the site is just broken on it's own,  
> but I
> do see a significant discrepancy in traceroutes from my network and  
> from
> he.net's looking glass.  Perhaps this would be a good chance to help  
> me
> learn how to debug my routes better.  Just let me know if this is a  
> lost
> cause without hinet.net's help.  Here's from my machine:
>

My company is running the 6to4 relay it looks like you're using.  
(based on the 2001:4978:1:410::ffff showing up in the traceroutes -  
that's us).

I can reach 2001:b000::1021 just fine natively. I've rerouted our  
connection a few times, and I can reach them fine through native v6  
without any problem.

I can't reach them from a 6to4 box - either from our 6to4 relay or  
another one I have access to. So, my best guess is that their route to  
2002::/16 is broken. That's the problem with 6to4 though, you can't  
really tell where the problem is unless you have help from several  
sides.

I moved the route for that /32 to a different upstream for us, but it  
didn't seem to help things here. If you'd like some more assistance in  
troubleshooting this, contact me off list and I'll see if I can get  
more people involved.

-- Kevin