Two factor authentication in FortiADC using open radius

[aagrafi]

Hello,

Reading the FAD admin guide, I understand that two factor authentication is supported using the FortiAuthenticator RADIUS service. Since RADIUS is an open standard, should this work also with any other RADIUS server like open RADIUS? In the FAD admin guide I don't see anything in the FAD's RADIUS configuration to limit it with FortiAythenticator only.

Thanks