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Chapter 11Fact Four—Interface ConfigurationIf you are new to IPv6, you will be shocked to see an IPv6 address, telling yourselfthat you are in trouble assigning addresses to interfaces or remembering theaddresses. However, it is not all that hard. In most cases, you can have your hostautoconfigure IPv6 address on its interfaces. Typically, you should set this up onlyon your network gateway (router) manually.Using IPv6Running FreeBSD 7, the kernel is already IPv6 enabled. However, you shouldmanually enable IPv6 in the UserLand, by adding the following line to the/etc/rc.conf configuration file:ipv6_enable="YES"And manually start the appropriate rc script (or reboot the system) for the changes totake effect:# /etc/rc.d/network_ipv6 startThis will enable IPv6 on all interfaces that are IPv6 capable. This behavior is changedby modifying the following variable in the /etc/rc.conf file:ipv6_network_interfaces="fxp0 bge0"This will enable IPv6 support on specified interfaces. The default value for thisvariable is auto.Once you enable IPv6, interfaces will discover the IPv6 enabled routers on thenetwork and build their own IPv6 addresses based on the network prefix theyreceive from the router.Configuring InterfacesIn a typical scenario, IPv6 network stack will automatically look for an IPv6 enabledrouter on the same network for each interface and try to automatically configure theIPv6 address on the interface.The following is an example of an automatically configured interface:# ifconfig ed0ed0: flags=8843 metric0 mtu 1500ether 00:1c:42:8d:5d:bf[ 177 ]