With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fnUserRadAddr
fn User Rad Address
1.3.6.1.4.1.12356.3.2.1.3
Host name or IP addr of the radius server
Back to FORTINET-MIB MIB page.
IPHost Network monitor allows you to monitor fnUserRadAddr on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet WAN extenders right now.