ipv6.he.net never loads but ipv6.google.com does

[skiss0rz]

I'm having a very odd problem. I am able to ping ipv6.he.net, ipv6.google.com, ipv6.sixxs.net all with below 100 ms through my tunnel. My tunnel endpoint is a cisco router and I'm using the first address of my routed /48 on the inside interface. My wired clients are plugged into the inside interface with the second and third addresses of the /48, and they can ping any ipv6 address I throw at them.

The weird part is the clients can load ipv6.sixxs.net and ipv6.google.com just fine (albeit a little slow, maybe indicative of the problem), but will not load the ipv6.he.net page at all beyond the title. The browser tab shows "Hurricane Electric IPv6 Certification", but the page stays blank forever. When I look at wireshark packet captures I see a lot of TCP Dup ACK and TCP Retransmission between my computer and the ipv6.he.net resolved ipv6 address.

After googling I've found some people fixing these errors by changing the MTU either of their client or the tunnel interface. I've tried lowering the MTU of both and it hasn't changed the problem at all. Does anyone have any idea what could be causing this?

[skiss0rz]

Nevermind I figured it out. It was just my ghetto Cisco 1751 garbage router.