With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgVpnSslStatsMaxWebSessions
fg Vpn Ssl Stats Max Web Sessions
1.3.6.1.4.1.12356.101.12.2.3.1.5
The maximum number of active SSL web sessions at any one time within the virtual domain
Back to FORTINET-FORTIGATE-MIB MIB page.
IPHost Network monitor allows you to monitor fgVpnSslStatsMaxWebSessions on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet access points right now.