Here are the steps to enable NetFlow on a Fortinet FortiGate firewall:
Login to the FortiGate firewall web interface.
Navigate to the System > Config > Network > Interfaces section.
Edit the interface that you want to enable NetFlow on.
Under the Advanced section, select NetFlow from the drop-down menu.
Enable NetFlow and select the version of NetFlow you want to use (version 5 or version 9).
Configure the NetFlow options, such as the NetFlow server IP address, the collector port, and the active timeout.
Click OK to save the changes.
Verify that NetFlow is working by checking the NetFlow statistics in the System > Monitor > NetFlow section of the web interface.
Note: The exact steps to enable NetFlow on a Fortinet FortiGate firewall may vary depending on the specific model and software version you are using. It's recommended to consult the manufacturer's documentation for specific instructions.