How to configure a 3G modem in a fortigate USB port

How to configure a 3G modem:

Firstly, ensure that your modem is firmly plugged into a USB Port on the back of the Fortigate, and that you've power-cycled the unit to detect the modem. You'll need to enable the modem with the following command:

config system modem
set status enable
end

Next, try and detect the custom vendor and product IDs with the following command. Be sure to note it down, as you'll need it later!

FortiGate # diagnose sys modem wireless-id
vendor: 0x12d1, product: 0x1003, registered: yes

Next, we'll configure the modem settings in our FortiGate to activate the modem connection:

config system modem
set status enable
set dial-on-demand enable
set connect-timeout 30
set wireless-custom-vendor-id 0x12d1
set wireless-custom-product-id 0x1003
set modem-dev1 pcmcia-wireless
set phone1 "*99#"
set username1 "3services" # Set this to your provider's APN
set altmode disable
end

We're almost there! The last thing to do is to turn on debugging (to watch the progress of the dial), and to actually execute the dial:

diagnose debug enable
diagnose debug application ppp 255
diagnose debug app modemd 255

execute modem dial

Once you're done, don't forget to turn off your logging:

diagnose debug application modemd 0
diagnose debug application ppp 0
diagnose debug disable

And that's it!