With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fnNidsSigUserDefTable
fn Nids Sig User Def Table
1.3.6.1.4.1.12356.5.1.3
User defined signature table
Back to FORTINET-MIB MIB page.
IPHost Network monitor allows you to monitor fnNidsSigUserDefTable on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet firewalls right now.