Hi, I'm not sure if you've got this resolved yet, but I had a very similar requirement to route Multicast traffic between two different networks. I found that we could get multicast sessions working fine from our Cisco switches, but when it needed to be routed, it wouldn't work. After going through the switch logs, it became apparent that the default IGMP query interval on the switches and the PA firewall are different. It was 60 seconds on the switches and 125 seconds on the firewall. These query intervals need to be synchronous for it to work. After setting it to 60 seconds on the firewall, I could get multicast sessions working over different networks, routed by the firewall. I took the example they gave here: https://live.paloaltonetworks.com/docs/DOC-4197 which is designed for multcasting between two PA firewalls and re-accomodated it for multicast routing on just 1 firewall.
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