nanog mailing list archives

Re: Denic (.de) blocking 6to4 nameservers (since begin feb 2010)


From: Tim Chown <tjc () ecs soton ac uk>
Date: Tue, 16 Feb 2010 14:00:13 +0000

On Tue, Feb 16, 2010 at 08:14:13AM +0100, Mikael Abrahamsson wrote:
On Tue, 16 Feb 2010, Nathan Ward wrote:

Perhaps they have Teredo and 6to4, and could not reach you via 6to4 so 
instead used Teredo, or, any number of scenarios.

I think their only IPv6 connectivity was Teredo (for instance, they're 
behind NAT), and thus they used it to get the IPv6 only content.

So for our case here at Southampton our web presence www.ecs.soton.ac.uk
is advertised via both A and AAAA records.

What we see is less than 1% of our IPv6 traffic coming from the Teredo
prefix.   6to4 is at most 1%.   I think the reason we see less 6to4 than
some might expect is that a lot of our IPv6 accesses may be from other
academic networks where IPv6 is available 'properly'.

I had our web guys send me a log of recent Teredo accesses to our servers
and the user agents were varied.    As Tore suggested, Opera 9.8 was
on the list (since fixed), but also some Mozilla-based entries from both
Linux and Windows platforms.

Total entries:  761
Opera 9.8:  354 
Firefox 3.5.7 (Windows):  61
Firefox 3.5.7 (Linux): 96
Iceweasel 3.5.6 (Linux): 8
Mozilla 4.0 (Windows): 242

Not a huge sample, but it shows Windows UAs hitting us from the Teredo
prefix.

-- 
Tim


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