With IPHost Network Monitor you can run simple snmp requests against a IBM device in your network.
ipSecTunnelHistInDropPkts
ip Sec Tunnel History In Dropped Packets
1.3.6.1.4.1.2.6.119.4.9.4.2.1.11
The number of packets dropped during received processing.
Back to ibm-ipsec MIB page.
IPHost Network monitor allows you to monitor ipSecTunnelHistInDropPkts on IBM device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring IBM switches right now.