How to automatically configure IPv6

[Chuck Musser]

> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 192.168.1.234  netmask 255.255.255.0  broadcast 192.168.1.255
>         inet6 2001:da8:8000:6440::1188  prefixlen 128  scopeid 0x0<global>
>         inet6 fe80::49a6:fb37:128a:a30b  prefixlen 64  scopeid 0x20<link>
>         ether fc:aa:14:dc:35:1a  txqueuelen 1000  (Ethernet)
> 
> However, I cannot make my DFly box with IPv6 automatically configured. 
> Here is my related settings in "/etc/rc.conf"(**):
> 
A sysctl option instructs the kernel to accept IPv6 router advertisements:

net.inet6.ip6.accept_rtadv=1

You can use the sysctl program to set this value by hand, but you’ll probably want to simply add the above line to /etc/sysctl.conf and reboot.