You may have IP multicast support and all the MBONE tools running, but that doesn’t mean you can tune in on NASA’s next shuttle mission on the MBONE. Chances are, none of those packets will make it to the network you are on.

First of all, the routers that connect your own subnets will have to be set up to forward multicast packets. For most modern routers this is simply a matter of changing a setting. However, some older routers may not be able to support multicast packets. If this is the case, or if your Internet Service Provider cannot forward MBONE packets to you, you will need to set up a tunnel to another network that is already part of the MBONE.

To connect to the MBONE on the Internet, you may have to go through your companies firewall. This is usually just a matter of setting up some packet filtering, or maybe a dual-homed host running mrouted.