With IPHost Network Monitor you can run simple snmp requests against a Netscreen device in your network.
nsNatDipTable
NETSCREEN Nat Dip Table
1.3.6.1.4.1.3224.11.2
A DIP(Dynamic IP) pool is a range of IP addresses from which the NetScreen device can dynamically take addresses to use when performing NAT on the source IP address of outgoing or incoming IP packets.
Back to NETSCREEN-NAT-MIB MIB page.
IPHost Network monitor allows you to monitor nsNatDipTable on Netscreen device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Netscreen VPN routers right now.