With IPHost Network Monitor you can run simple snmp requests against a Netscreen device in your network.
nsIfFlowInVpn
NETSCREEN If Flow In Vpn
1.3.6.1.4.1.3224.9.3.1.7
VPN packet go through this interface
Back to NETSCREEN-INTERFACE-MIB MIB page.
IPHost Network monitor allows you to monitor nsIfFlowInVpn 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.