Multicast forwarding to set top box behind the FG81e

[G00dm]

Hi all, 

I have below issue.

My internet provider also provides the TV service via multicast using IPTV STBs (set top boxes).

The router by the provider bridging WAN port with STB port as L2 switch.
In result the STB get its IP details from vendor whitelisted DHCP which is different than standard WAN IP of the router delivered by DHCP. 
Unfortunately if I put the STB behind the SD-WAN I cant get it connect to the IPTV service.

I don't see way how I can add L2 ports to WAN like I can do in Mikrotik. 
Please advise if I can solve somehow this conundrum without to put additional L2 switch between the provider and WAN port of my FG81e.

Regards, G00dman

[akristof]

Hello,

Thank you for your question. Well, this can be a bit tricky. If ISP is sending directly multicast and you don't need to play with igmp, it should be enough if you will create multicast policy and forward it from wan port to your STB port. But it depends entirely how ISP is sending IPTV traffic.

[G00dm]

May I ask you for advice how to do it?

[akristof]

Hi,

Here is example and some documentation"

https://docs.fortinet.com/document/fortigate/6.2.5/cookbook/968606/configuring-multicast-forwarding