To use IPv6, the following modules may or may not be necessary:

• IPv6 kernel module (always)
• IPv6 routing software (always, to configure IPv6 routing)
• ip6tables kernel modules (optional, if you need an IPv6 firewall)
• ip6tables command-line tool (optional, to configure the IPv6 firewall)

opkg install kmod-ipv6 radvd ip kmod-ip6tables ip6tables

When the configuration is done according to the method in use, from the router the command ping6 ipv6.google.com should work.

If it does not work but ping6 [2a00:1450:8002::93] does, it means that your DNS server is not resolving IPv6 addresses at all: changing it will be necessary (please see the relevant chapter below).

When using a firewall, don't forget to check that IPv6 is enabled:

config defaults option syn_flood 1 option drop_invalid 1 option input ACCEPT option output ACCEPT option forward REJECT # Uncomment this line to disable ipv6 rules # option disable_ipv6 1

To enable basic IPv6 support in OpenWRT Backfire (10.03), install the IPv6 kernel module using the shell:

root@OpenWrt:/# opkg install kmod-ipv6

root@OpenWrt:/# /etc/init.d/network restart

Verify by running ifconfig and making sure there are inet6 addresses listed:

root@OpenWrt:/# ifconfig
eth0      Link encap:Ethernet  HWaddr <hwaddr>
          inet addr:192.168.0.211  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: <globaladdr> Scope:Global
          inet6 addr: <linklocaladdr Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:110 errors:0 dropped:0 overruns:0 frame:0
          TX packets:21 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:12632 (12.3 KiB)  TX bytes:1966 (1.9 KiB)
          Interrupt:10 Base address:0x4000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:5 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:496 (496.0 B)  TX bytes:496 (496.0 B)

To forward packets between interfaces, a kernel-level setting must be enabled. Insert the following line to /etc/sysctl.conf:

net.ipv6.conf.all.forwarding=1

and reboot or execute /etc/init.d/sysctl start to commit your changes. To verify, cat /proc/sys/net/ipv6/conf/all/forwarding needs to return 1.

• http://www.kernel.org/doc/Documentation/networking/ipv6.txt
• http://lxr.free-electrons.com/source/Documentation/networking/ipv6.txt
• http://wiki.debian.org/DebianIPv6