How to Configure Broadcast Forwarding in Fortinet Firewall

Re-broadcasting, also known as broadcast forwarding, allows the firewall to transmit broadcast traffic between different network segments. In this post, we’ll guide you through the process of enabling re-broadcast on a Fortinet firewall. Also a quick example of Checkpoint Clish to achieve the same result.

Scenario Diagram and Requirement

  • GPS station is sending UDP traffic to a broadcast IP address, so all machines within can see the traffic, it can be a UDP packet with a non-standard port number.
  • The UDP packet needs to travel over the core switch then the Fortinet firewall
  • Fortinet FW then re-broadcasts the packet so the server and clients within the VLAN subnet can receive it
  • Assume routing is working normally between and

Solution Step 1

Enable broadcast forwarding on the ingress interface ONLY, NO need to do anythong on the egress interface.

config system interface
    edit "port1"
        set ip
        set broadcast-forward enable
    edit "port4"
        set ip

Solution Step 2

Then create a standard IPv4 unicast firewall policy to allow the traffic from to

Similar Funcitonlity on Checkpoint Firewall

Under Checkpoint Clish, type the comand below and save the config

set iphelper forward-nonlocal on

set iphelper interface bond0 udp-port 50000 relay-to on

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