With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cermResUserTypeResUserCount
Cisco Embedded Resource Manager Resource User Type Resource User Count
1.3.6.1.4.1.9.9.510.1.2.4.1.5
This object indicates the number of resource users instantiated from the resource user type. This object value will be equal to the number of resource user entries present in the cermResUserTable for the resource user type.
Back to CISCO-ERM-MIB MIB page.
IPHost Network monitor allows you to monitor cermResUserTypeResUserCount on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.