Techniques are described for supporting PIM (Protocol Independent Multicast) Dense Mode (PIM-DM) and PIM Bootstrap Router (PIM-BSR) between different VPN sites of an IP VPN. A system includes a plurality of customer sites connected to a service provider network by provider edge (PE) routers that provide an IP VPN. A first one of the PE routers receives multicast traffic from a first one of the customer sites, wherein the multicast traffic is PIM (Protocol Independent Multicast) Dense Mode (PIM-DM) traffic for which no PIM join messages have been received by the first PE router from the other PE routers via BGP messages. A tunnel setup module of the first PE router is configured to automatically signal a provider tunnel through the service provider network upon receiving the PIM-DM multicast traffic without maintaining multicast state data for a multicast group associated with the PIM-DM multicast traffic.