With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ceaPortTable
Cisco Ethernet Access Port Table
1.3.6.1.4.1.9.9.466.1.2.1
This table contains Ethernet port specific information. There exists an entry for each Ethernet port with an ifType of 6 (ethernetCsmacd) in this table. Note that the maximum number of NNI ports that can be configured per module on this device is given by the value of ceaMaxNNIPorts.
Back to CISCO-ETHERNET-ACCESS-MIB MIB page.
IPHost Network monitor allows you to monitor ceaPortTable 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.