With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swLoopDetectTrapMode
Switch Loop Detect Trap Mode
1.3.6.1.4.1.171.12.41.1.5
This object indicates the loopback detection trap mode for the system.
Back to LOOPBACK-DETECT-MIB MIB page.
IPHost Network monitor allows you to monitor swLoopDetectTrapMode 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.