My latest toy is a Asus RT-N66U Dark Knight router. While it’s ever so nice to have a router that’s configurable via telnet and obviously Linux based, IPv6 is a little harder than on an Airport. This is made messier by their having changed the interface at some point, so it’s all a bit of a kerfuffle.

So, without further ado, here’s a quick guide on configuring the RT-N66U with a Hurricane Internet TunnelBroker IPv6 tunnel on the latest firmware (

On the IPv6 tab:

  • Connection Type: Tunnel 6rd
  • DHCP Option: Disable
  • IPv6 Prefix: The address part of the Routed /48 address of your tunnel, e.g. 2001:123:abcd::
  • IPv6 Prefix Length: 48
  • IPv4 Border Router: The Server IPv4 Address address of your tunnel.
  • IPv4 Router Mask Length: 24
  • Tunnel MTU: The default, unless you’ve changed it on the Advanced tab for your tunnel. e.g. on BT Infinity this should be 1472 on both ends.
  • Tunnel TTL: 255
  • IPv6 DNS Server 1: Your choice, I favour Google: 2001:4860:4860::8888
  • Enable Router Advertisement: Enable

If you’re on a dynamic WAN IP address (thanks BT) you’ll also need to set up DynDNS.

On the WAN -> DDNS tab:

  • Host Name: The ID of your tunnel, e.g. 12345.
  • User Name or E-mail Address: Your hex user ID (not your username), from the Main Page on TunnelBroker.
  • Password: Your TunnelBroker password.

Alternately, you can do it manually whenever it changes via:

curl -4 "https://<username>:<password><tunnelid>"

Do please note: the router leaves IPv6 access open, so you’ll want to either configure rules on ip6tables on the router, or to ensure everything on your LAN is firewalled. Caveat emptor.