With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cipIpForwarding
Cisco Channel Interface Processor Ip Forwarding
1.3.6.1.4.1.9.9.32.1.1.1.1.2
The indication of whether this entity is acting as an IP gateway in respect to the forwarding of datagrams received by, but not addressed to, this entity. IP gateways forward datagrams. IP hosts do not (except those source-routed via the host). Note that for some managed nodes, this object may take on only a subset of the values possible. Accordingly, it is appropriate for an agent to return a `badValue' response if a management station attempts to change this object to an inappropriate value.
Back to CISCO-CIPTCPIP-MIB MIB page.
IPHost Network monitor allows you to monitor cipIpForwarding on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco multiplexers right now.