With IPHost Network Monitor you can run simple snmp requests against a Netscreen device in your network.
nsPlyDstZone
NETSCREEN Ply Dst Zone
1.3.6.1.4.1.3224.10.1.1.4
Traffic through a firewall means that traffic flows from one security zone to another. This object describes the destination zone name traffic flow passes.
Back to NETSCREEN-POLICY-MIB MIB page.
IPHost Network monitor allows you to monitor nsPlyDstZone 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.