PIM vs multicast forwarding

[pbarbieri]

 One firewall in my LAN is configured with PIM dense mode and wish to communicate  with another firewall ( same model Fortigate 600D) but configured with multicast forwarding. Can the first node PIM enabled able to transfer and receive multicast traffic with the  second one? and how? If I set the first one in PIM dense passive mode can I resolve the problem?

[Anonymous]

Hello @pbarbieri , 

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible. 

Thanks, 

  Fortinet Community Team 

[alif]

Hi @pbarbieri,

Please create a multicast policy on Fortigate to allow encapsulated (multicast) packets or decapsulated data (IP traffic).

Please refer to the following links for deails:

https://docs.fortinet.com/document/fortigate/6.4.5/administration-guide/896987/multicast-routing-and...

https://docs.fortinet.com/document/fortigate/6.4.5/administration-guide/968606/configuring-multicast...

[pbarbieri]

Thank you very much for you reply. I am already using GRE to encapulated and decapsulated multicast packets. what it happens is that from no PIM node (multicast forwarding) the PIM enabled node receive correctly multicast packets, but not viceversa. I guess that the PIM enabled node attend the PIM join and refresh state packets from remote node to deliver to it the multicast packets, this is part of the protocol. I wondered if I can use a shortcut to force PIM enable node to send anyway multicast packet outside independently. 

[vponmuniraj · Accepted solution]

Hi,

Multicast forwarding allows multicast traffic forwarded from an interface towards an interface configured in the multicast policy. 

PIM Dense mode would need a active PIM neighbor. Depending on the setup, you might need to configure PIM dense mode on your 600D to forward multicast traffic. 

Regards,