When I ping any ipv6 host  f.ex.

root@sthlmgw:/opt/var# ping6 www.kame.net
PING www.kame.net (2001:200:0:8002:203:47ff:fea5:3085): 56 data bytes
--- www.kame.net ping statistics ---
35 packets transmitted, 0 packets received, 100% packet loss

tcpdump -i henet showes
13:29:58.962722 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 27, length 64
13:29:59.962729 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 28, length 64
13:30:00.962715 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 29, length 64
13:30:01.962729 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 30, length 64
13:30:02.962732 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 31, length 64
13:30:03.962733 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 32, length 64
13:30:04.962719 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 33, length 64
13:30:05.962732 IP6 2001:470:1f03:8c::2 > 2001:200:0:8002:203:47ff:fea5:3085: ICMP6, echo request, seq 34, length 64

mean while so it goes threw henet interface

root@sthlmgw:/opt/var# ip link
1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,PROMISC,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:1a:70:df:90:60 brd ff:ff:ff:ff:ff:ff
3: eth0.0: <BROADCAST,MULTICAST,PROMISC,UP> mtu 1500 qdisc noqueue
    link/ether 00:1a:70:df:90:60 brd ff:ff:ff:ff:ff:ff
4: eth0.1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
    link/ether 00:1a:70:df:90:60 brd ff:ff:ff:ff:ff:ff
5: br-lan: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
    link/ether 00:1a:70:df:90:60 brd ff:ff:ff:ff:ff:ff
6: wl0: <BROADCAST,MULTICAST,PROMISC,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:1a:70:df:90:62 brd ff:ff:ff:ff:ff:ff
7: tun0: <POINTOPOINT,MULTICAST,NOARP,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/[65534]
8: wl0.1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:1a:70:df:90:62 brd ff:ff:ff:ff:ff:ff
9: sit0@NONE: <NOARP> mtu 1480 qdisc noqueue
    link/sit 0.0.0.0 brd 0.0.0.0
12: henet@NONE: <POINTOPOINT,NOARP,PROMISC,UP> mtu 1480 qdisc noqueue
    link/sit 83.251.23.XX peer 64.71.128.83

root@sthlmgw:/opt/var# ip -6 route show
2001:470:1f01:140::/64 dev br-lan  metric 256  mtu 1500 advmss 1440
2001:470:1f03:8c::/64 via :: dev henet  metric 256  mtu 1480 advmss 1420
fe80::/64 dev eth0  metric 256  mtu 1500 advmss 1440
fe80::/64 dev eth0.0  metric 256  mtu 1500 advmss 1440
fe80::/64 dev br-lan  metric 256  mtu 1500 advmss 1440
fe80::/64 dev wl0  metric 256  mtu 1500 advmss 1440
fe80::/64 dev eth0.1  metric 256  mtu 1500 advmss 1440
fe80::/64 via :: dev henet  metric 256  mtu 1480 advmss 1420
ff00::/8 dev eth0  metric 256  mtu 1500 advmss 1440
ff00::/8 dev eth0.0  metric 256  mtu 1500 advmss 1440
ff00::/8 dev br-lan  metric 256  mtu 1500 advmss 1440
ff00::/8 dev wl0  metric 256  mtu 1500 advmss 1440
ff00::/8 dev eth0.1  metric 256  mtu 1500 advmss 1440
ff00::/8 dev henet  metric 256  mtu 1480 advmss 1420
default dev henet  metric 1024  mtu 1480 advmss 1420

In /etc/init.d/custom-user-startup

ip tunnel add henet mode sit remote 64.71.128.83 local $ipv4 ttl 255
ip link set henet up
ip addr add 2001:470:1F03:8c::2/64 dev henet
ip route add ::/0 dev henet
ip -f inet6 addr
ip -6 addr add 2001:470:1F01:140::/64 dev br-lan

in /etc/firewall.user

#!/bin/sh
# Copyright (C) 2006 OpenWrt.org

iptables -F input_rule
iptables -F output_rule
iptables -F forwarding_rule
iptables -t nat -F prerouting_rule
iptables -t nat -F postrouting_rule

# The following chains are for traffic directed at the IP of the
# WAN interface

iptables -F input_wan
iptables -F forwarding_wan
iptables -t nat -F prerouting_wan

iptables -t nat -D POSTROUTING -o $WAN -j MASQUERADE
iptables -t nat -A POSTROUTING --protocol ! 41 -o $WAN -j MASQUERADE

/etc/radvd.conf

# For more examples, see the radvd documentation.

interface br-lan
{
        AdvSendAdvert on;

#
# Disable Mobile IPv6 support
#
        AdvHomeAgentFlag off;
  #
    # These settings cause advertisements to be sent every 3-10 seconds.  This
      # range is good for 6to4 with a dynamic IPv4 address, but can be greatly
        # increased when not using 6to4 prefixes.
          #

                    MinRtrAdvInterval 3;
                              MaxRtrAdvInterval 10;

#
# example of a standard prefix
#
        prefix 2001:470:1F01:140::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
                AdvRouterAddr on;
        };

};

which kernel did you use? in 2.4. ipv6 was/is broken.

use ip6tables, not iptables, for firewall configuration

2.4 only i can use

i had the same problem. i finaly gave up and bought new hardware (2.6-compatible). sry, maybe someone else solved the problem

I have IPv6 working on 2.4. I have no complaints except there is no stateful firewalling like in 2.6.

I have added this to /etc/firewall.user:

ip6tables -F INPUT
ip6tables -P INPUT DROP
ip6tables -A INPUT -p tcp --dport 22 -j ACCEPT
ip6tables -A INPUT -p icmpv6 -j ACCEPT

ip6tables -F FORWARD
ip6tables -A FORWARD -j ACCEPT

New file /etc/init.d/network-ipv6:

#!/bin/sh /etc/rc.common
# Copyright (C) 2006 OpenWrt.org

START=46

start() {
        /usr/sbin/ip -6 addr add 2001:123:1234::1/48 dev br-lan
}

I use AICCU though which may do additional initialisation work I am not aware of.

@cereal what hardware did you buy?

2001:123:1234::1/48 thats the internal IP right?

hwo do you give out IPs on the internal network?

I have been assigned a /48 prefix which is 65536 /64 IPv6 networks all in all. I.e. I have about 2^80 IP addresses at my disposal. I just use one /64 network and in there picked .....::1 as IP for router. radvd is then announcing the route.

i bought an netgear wgt634u, but i will try ipv6 on the linksys wrt54gl again tomorrow. i hope bsdice was correct and it is working now (my atempts were 2 or 3 month ago).

to be more precise what worked and what not worked:

worked:
- etablishe tunnel to broker (sixxs via aiccu)
- "normal unroutet traffic (icmp)

not worked:
- routing packets from the subnet ( /64) via the tunnel into the internet
  - no icmp to "broker-tunnel-endpoint" and/or kame

Looks like a radvd config problem. Here is my radvd config:

interface br-lan
{
        AdvSendAdvert on;
        AdvLinkMTU 1280;
        MinRtrAdvInterval 5;
        MaxRtrAdvInterval 10;
        prefix 2001:dead:babe::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
                AdvRouterAddr on;
        };
};

Notice the /64 even though sixxs gave you a /48 (64k worth of /64 which you can use!).

Aiccu options I am using are: username, password, protocol tic, server tic.sixxs.net, ipv6_interface sixxs, rest is left at defaults. Worked for me right away.

FYI

        option ip6addr  2001:470:1F01:140::/64

is valid in the /etc/config/network file  ( one less line in your start up script )

i'm running 2.4 on an asus wl-500gp , tunnel into he.net with no issues and i even have xp machines on my lan getting addresses assigned to them ( radvd ) , AND xp machines can ping the outside world.
oh , and i get a dancing turtle on www.kame.net