Global Lambda Integrated Facility

Subject and IPv6 problems
From Chris Tracy <chris@xxxxxxxxxxxxxx>
Date Wed, 18 Feb 2009 11:03:51 -0500


I'm not sure who would be the best person to report this to, but we
noticed that DNS for returns both A and AAAA records, and
there appear to be some problems beyond when trying to access
the GLIF website from some sites within the US.

For example, from MAX (and anybody connected to us), if your host has
an IPv6 address and you try to reach, it seems to cross
the Atlantic but then gets stuck beyond

# traceroute6
traceroute to (2001:610:148:dead::6), 30 hops max, 80 byte packets
 1  2001:468:c00:6::1 (2001:468:c00:6::1)  0.432 ms  0.542 ms  0.634 ms
 2  2001:468:c00:5::2 (2001:468:c00:5::2)  1.581 ms  1.674 ms  1.765 ms
 3 (2001:504:0:2::1273:1)  3.077 ms  3.663 ms  3.077 ms
 4 (2001:5000:0:145::2)  95.519 ms  95.496 ms  95.507 ms
 5  * * *

We will do whatever we can at MAX to work around this, but I suspect
this might be a problem for other sites as well.

My experience with IPv6 is that most big websites (e.g. Google) do not
double-up their DNS entries like this.  Instead, they return the A
record for and the AAAA for
Unfortunately, that seems to be the state of things...

Replicating this for and might be a good
idea, to make sure that people do not have trouble accessing the GLIF

Fortunately, this does not seem to be a problem from
Internet2-connected sites, as I can ping/traceroute to
2001:610:148:dead::6 from the Internet2 router proxy.


Chris Tracy
Mid-Atlantic Crossroads (MAX)
Office phone: 301.314.6655
GPG key: 0xB3B9C93D

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