With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
mauIfGrpHCStats
mau If Group HC Stats
1.3.6.1.2.1.26.6.1.2.12
MAUs attached to interfaces
Back to MAU-MIB MIB page.
IPHost Network monitor allows you to monitor mauIfGrpHCStats 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.