Blocking IPv6 Mroutes

By default, when an interface receives multicast traffic, even when the scope of that traffic exceeds link-local, the virtual router creates an mroute. You can use the ipv6 block-multicast-sources command to block all multicast traffic with a scope larger than link-local (for example, global) and prevent mroute creation under these conditions.

Note: Issuing this command does not affect reception of link-local multicast packets.

To block all multicast traffic with a scope larger than link-local:

• Issue the ipv6 block-multicast-sources command in Global Configuration mode.
  host1(config)#ipv6 block-multicast-sources

Use the no version to restore the default behavior of creating mroutes on receiving multicast packets.