Setting up IPv6 Tunnel with Hurricane Electric (Tunnelbroker.net)

2) Register/Login

3) Create Regular Tunnel
    -> IPV4 Endpoint (Your Side)
    Enter Public IP Address, example: 9.33.21.35
    Selection a tunnel endpoint that's closest to you example: Los Angeles, CA, US
    
    If you have a firewall allow ICMP packets from source IP: 66.220.2.74 with, 
    # iptables -A INPUT -p icmp -s 66.220.2.74 -j ACCEPT

On the Main Page, under the tunnel you just created you get following information:

    Server IPv4 Address: 74.82.46.6
    Server IPv6 Address: 2001:1337:24:3ac::1/64
    Client IPv4 Address: 9.33.21.35
    Client IPV6 Address: 2001:1337:24:3ac::2/64

    Routed /64: 2001:db8:12:413::/64
    
    Configure your firewall to allow traffic from 74.82.46.6 endpoint.
    # iptables -A INPUT -p ip -s 74.82.46.6 -j ACCEPT

This is sufficient information to create an IPv6 Tunnel.

Setting up IPv6 Tunnel on Debian/Ubuntu:
----------------------------------------
This below is a Debian/Ubuntu specific guide. It may or maynot work on other Linux flavors.

1) Edit /etc/network/interfaces file (# vim /etc/network/interfaces)

## Add these lines below to setup a tunnel to your endpoint from information gathered above
auto mytunnel0
iface mytunnel0 inet6 v4tunnel
  address 2001:1337:24:3ac::2
  netmask 64
  endpoint 74.82.46.6
  up ip -6 route add default dev mytunnel0
  down ip -6 route del default dev mytunnel0

# This is network configuration for your default network interfaces. Leave it the way it is.
auto eth0
iface eth0 inet dhcp

# Add these lines to assign a static ipv6 address to your network interface from your very own routed /64 subnet.
iface eth0 inet6 static
  address 2001:db8:12:413::1
  netmask 64
  
############EOF################
 
That's it. if you want to load it without rebooting the server:
 # ifup mytunnel0
 # ifdown eth0 && ifup eth0
 
 or, reboot
 # reboot
 
 Setting up IPv6 Tunnel on FreeBSD/PC-BSD
 -----------------------------------------
 Using /etc/rc.conf: 
 ============
    ## Edit /etc/rc.conf and add these lines according to the tunnel information above:
    ipv6_enable="YES"
    ipv6_gateway_enable="YES"
    ipv6_network_interfaces="lo0 gif0"
    ipv6_ipv4mapping="YES"
    gif_interfaces="gif0"
    gifconfig_gif0="9.33.21.35 74.82.46.6"
    ipv6_ifconfig_gif0="2001:1337:24:3ac::2 2001:1337:24:3ac::1 prefixlen 128"
    ipv6_defaultrouter="2001:1337:24:3ac::1"

    # Assuming your default network interface is re0, add this line to assign an address from /64 subnet allocated to you.
    ifconfig_fxp0_alias0="inet6 2001:db8:12:413::1 prefixlen 64"

Using script: 
============
#!/usr/local/bin/bash
# Script: /root/ipv6_tunnel.sh
ifconfig gif0 create
ifconfig gif0 tunnel 9.33.21.35 74.82.46.6
ifconfig gif0 inet6 2001:1337:24:3ac::2 2001:1337:24:3ac::1 prefixlen 128
route -n add -inet6 default 2001:470:1f04:1cf4::1
ifconfig gif0 up

ifconfig re0 inet6 2001:db8:12:413::1 prefixlen 64 alias

If you are planning to bind your services/applications on both IPv4 and IPv6 sockets, it's necessary to tune in some sysctl values.

On GNU/Linux: 
-------------
# sysctl -w net.ipv6.bindv6only=0
# echo net.ipv6.bindv6only=0 >> /etc/sysctl.conf

On FreeBSD/PC-BSD:
------------------
# sysctl -w net.inet6.ip6.v6only=0
# echo net.inet6.ip6.v6only=0 >> /etc/sysctl.conf

Testing IPv6 Connectivity: 
--------------------------
 $ ping6 ipv6.google.com