With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swL3IpCtrlSecondary
Switch L3 Ip Control Secondary
1.3.6.1.4.1.171.11.70.5.3.2.1.3.1.7
When this is true(1) the IP address is the secondary IP. When false(2), the IP address is the primary IP.
Back to SWL3MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor swL3IpCtrlSecondary on D-Link device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring D-Link VPN routers right now.