Technical Note: Forwarding multicast traffic in NAT mode

[Sandeep_FTNT]

Description

Applications like Bonjour (used for airplay, airprint, apple TV), dynamic routing protocols, and video streaming use multicast traffic for communication.  This knowledge article explains how to forward multicast traffic on a FortiGate device.

Scope

FortiGate v4.0 and above.

Solution

It is assumed that multicast traffic needs to be allowed from Port1 to DMZ.

Procedure

Step 1

Enable multicast forwarding from CLI using the following commands:

config system setting
set multicast-forward enable
set multicast-ttl-notchange enable
end

Step 2

Configure multicast policy for source and destination.

From GUI:

Navigate to Policy & Objects > Multicast > Create New.  Select the source and destination interface with source and destination IP address.

Note: If the Multicast tab is not seen then Navigate to System > Config > Features.  Enable Multicast policy to get it on the GUI.

From CLI:

config firewall multicast-policy
edit 1
set srcintf  port1
set dstintf  dmz
set srcaddr  all
set dstaddr  all
next
end