With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cnatConfDynAddrMapEntry
cnat Config Dyn Address Map Entry
1.3.6.1.4.1.9.10.77.1.1.3.1
A description of a dynamic NAT entry. This entry contributes to the dynamic NAT table of the device.
Back to CISCO-IETF-NAT-MIB MIB page.
IPHost Network monitor allows you to monitor cnatConfDynAddrMapEntry on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.