.--------. net1 .----. net2 .----. net3 .----------.
The networks between the boxes are actually Linux bridge devices (br), on which you may have to disable IGMP/MLD snooping to get pimd to run smoothly. Only R2 and R3 run FreeBSD v10.2, 64-bit. The net1, between sender and R2, and net3, between R3 and the receiver, are both setup using simple DHCP client. The Linux bridges have a DHCP server running. Only net2 between the two routers is static, using 20.30.0.0/24.
You need a few things set up in FreeBSD before starting pimd.
See the OpenBSD HowTo for example output and troubleshooting.