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Chapter 11Multicast RoutingThe ability to route multicast traffic in FreeBSD 7 is available using third-partysoftware that can be used from ports collection. The net/mcast-tools port allowsProtocol Independent Multicast Sparse-Mode (PIM-SM Version 2), PIM-Source-Specific Multicast (SSM using PIM-SM), and Protocol Independent MulticastDense-Mode (PIM-DM Version 2) routing.Once installed, the functionality is enabled by adding this line to /etc/rc.conf:mroute6d_enable="YES"This will automatically enable the pim6dd(8) (dense mode) daemon. If you areplanning to use pim6sd(8) (sparse mode), you should also add the following line to/etc/rc.conf:mroute6d_program="/usr/local/sbin/pim6sd"TunnelingThere are certain cases where you want to set up a tunnel to transport IPv6 trafficover your existing IPv4 network. This can be a site-to-site VPN between two IPv6enabled networks, or getting IPv6 connectivity to an IPv6 service provider. There aredifferent methods by which you can set up such tunnels. The most popular methodsare gif(4), faith(4), and stf(4).GIF TunnelingThere are chances that you do not have native IPv6 connectivity to the internet. Inthat case, you can still set up a non-native (tunneled) IPv6 connection to the internet.There are several services that offer tunneling to IPv6 networks, such aswww.sixxs.net. The only thing you should do is to sign up for such a serviceand set up a tunnel internet according to their instructions.This is mostly done by encapsulating IPv6 traffic over a gif(4) tunnel that isestablished over IPv4 to the other end. In most cases, setting up such connectivity ispretty straightforward.[ 181 ]