I've got four tunnels, which generally work great. Two are to home routers, which dole out addresses from the /64, and two are to servers.
They all can get to various IPv6 hosts (ipv6.google.com,
www.kame.net) with no problem. There are six possible connections between the four networks, and five of those connections work great. But there's one pair of tunnels that can't talk with each other.
Ping fails. TCP connections actually succeed, but only after waiting a loooong time.
Here's a trace from an autoconfigured machine on the 2001:470:1f0f:41e::/64 network to 2001:470:1f04:9dc::2:
traceroute to 2001:470:1f04:9dc::2 (2001:470:1f04:9dc::2), 30 hops max, 40 byte packets
1 2001:470:1f0f:41e::1 (2001:470:1f0f:41e::1) 0.823 ms 1.952 ms 2.453 ms
2 2001:470:1f0e:41e::1 (2001:470:1f0e:41e::1) 66.509 ms 70.611 ms 75.823 ms
3 gige-g2-14.core1.dal1.he.net (2001:470:0:78::1) 76.376 ms 76.520 ms 77.360 ms
4 10gigabitethernet1-2.core1.lax1.he.net (2001:470:0:3a::1) 109.156 ms 109.640 ms 110.471 ms
5 10gigabitethernet1-3.core1.pao1.he.net (2001:470:0:34::1) 117.231 ms 117.637 ms 128.805 ms
6 gige-g1-4.core1.fmt2.he.net (2001:470:0:30::1) 120.205 ms 119.935 ms 119.250 ms
7 1g-bge0.tserv3.fmt2.ipv6.he.net (2001:470:0:45::2) 119.886 ms 108.530 ms 113.776 ms
8 * * *
9 * * *
10 * * *
11 * * *
etc etc.
It fails on multiple machines on the 2001:470:1f0f:41e::/64 network, including a laptop that works on the other network. Is there something I'm doing wrong on the router? Thanks.
EDIT - Correction: I believe the TCP connection eventually works because it's giving up on IPv6 and uses IPv4.