With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swQinQRuleSourcePort
Switch Qin Q Rule Source Port
1.3.6.1.4.1.171.12.57.4.2.1.15
Specifies the source port number.
Back to Q-IN-Q-MIB MIB page.
IPHost Network monitor allows you to monitor swQinQRuleSourcePort 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.