FC10 - problems with ping6 and traceroute6

[Robert Moskowitz]

I have a FC10 system that is set up for IPv6 only (IPv4 only on 
localhost).  Its /etc/resolv.conf has the IPv6 address of a namecaching 
DNS server with IPv4 connectivity so it can reach all those DNS servers 
out in the cloud....

Anyway.

So I am trying to setup yum update to run to a IPv6 mirror, trying 
mirror.cc.vt.edu first.  So I 'ping6 -n mirror.cc.vt.edu' and get 
'unknown host'.  I try 'host mirror.cc.vt.edu' and get:

mirror.cc.vt.edu is an alias for chernabog.cc.vt.edu.
chernabog.cc.vt.edu has address 198.82.161.58
chernabog.cc.vt.edu has IPv6 address 2001:468:c80:2105:0:25e:42da:ffc7
chernabog.cc.vt.edu mail is handled by 0 chernabog.cc.vt.edu.

So I try 'traceroute6 -n mirror.cc.vt.edu' and get:

mirror.cc.vt.edu: Temporary failure in name resolution
Cannot handle "host" cmdline arg 'mirror.cc.vt.edu' on position 1 (argc 2)

I then try 'traceroute6 -n 2001:468:c80:2105:0:25e:42da:ffc7' and get 
there in 11 hops.

So why the name resolution failure?  Firefox won't connect either.  I 
have not tried yum.

Is it the namecaching server's 'fault'?  I can ping6 this host from this 
notebook (running Centos) that is duo-stack and uses an IPv4 only 
nameserver (that is the master from my zone).