With IPHost Network Monitor you can run simple snmp requests against a Netscreen device in your network.
nsNatMipNetmask
NETSCREEN Nat Mip Netmask
1.3.6.1.4.1.3224.11.1.1.3
Subnet mask for this MIP.
Back to NETSCREEN-NAT-MIB MIB page.
IPHost Network monitor allows you to monitor nsNatMipNetmask on Netscreen device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Netscreen firewalls right now.