With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgVpnSslStatsLoginUsers
fg Vpn Ssl Stats Login Users
1.3.6.1.4.1.12356.101.12.2.3.1.2
The current number of users logged in through SSL-VPN tunnels in the virtual domain
Back to FORTINET-FORTIGATE-MIB MIB page.
IPHost Network monitor allows you to monitor fgVpnSslStatsLoginUsers on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet switches right now.