With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swLoopDetectAdminState
Switch Loop Detect Admin State
1.3.6.1.4.1.171.12.41.1.1
This object indicates the loopback detection status for the system.
Back to LOOPBACK-DETECT-MIB MIB page.
IPHost Network monitor allows you to monitor swLoopDetectAdminState 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.