See the attached diagram. I have a multicast source (PC#1) connected to a subinterface on a router, via a switch. The IP address for PC#1 192.168.0.200 must be NAT'd to 10.1.1.200. The traffic is GRE tunnelled to another switch (6500) and then on to PC#2. The interface and the Tunnel on the 7200 are in vrf ABCD. Multicast is running in sparse-mode. From PC#1 I can ping PC#2 and the source address is NAT'd OK. PC#2 can subscribe to PC#1 multicast feed but the multicast UDP packets source address is not NAT'd. I have also tried NAT Virtual Interface on the incoming subinterface but this does not work either. I wonder if anyone can help?