FreeBSD config
--------------

Install the dual-dhclient port:
$ fetch http://daemonology.net/tmp/dual-dhclient.tgz
$ tar -xf dual-dhclient.tgz -C /usr/ports
$ make -C /usr/ports/net/dual-dhclient install

Edit /etc/rc.conf:
* change ifconfig_DEFAULT line:
	ifconfig_DEFAULT="SYNCDHCP accept_rtadv"
* add the following two lines:
	ipv6_activate_all_interfaces="YES"
	dhclient_program="/usr/local/sbin/dual-dhclient"

AWS config
----------

1. Add an IPv6 CIDR to your VPC.

2. Add an IPv6 CIDR to each subnet.

3. Enable auto-assign IPv6 address on each subnet.

4. Adjust the Route Table by adding a destination of ::/0 with a Target of
the VPC's Internet Gateway.

5. (If necessary) Adjust your Security Group rules to allow IPv6 traffic.