This is a quick walk-through/tutorial for configuring a Protocol 41 tunnel (from tunnelbroker.net) on a D-Link DIR-825 (rev. B) NAT appliance.
Step 1, log into your appliance and under the “Setup” tab, you’ll see a link for “IPv6”.
Step 2, after selecting “IPv6” in the setup menu, you will be presented with 2 options for configuring IPv6 on the appliance: Wizard and Manual. Select the manual configuration link.
Step 3, on this configuration menu, select “IPv6 in IPv4 Tunnel” as connection Type. Refer to your tunnel’s details page to fill in the blanks:
Server IPv4 Address = Remote IPv4 Address
Server IPv6 Address = Remote IPv6 Address
Client IPv6 Address = Local IPv6 Address
Routed /64 = LAN IPv6 Address (make certain IP ends as ::1 without the netmask)
Then save your settings and IPv6 will be made available to all your hosts connected to the DIR-825, both wired and wireless.
There still doesn’t appear to be any kind of IPv6 firewall rules to configure on the DIR-825, so make certain your hosts are secured using their own protection methods (ip6tables for Linux, Windows Firewall, etc.).