With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swPimIpMRouteSourceMask
Switch Pim Ip M Route Source Mask
1.3.6.1.4.1.171.12.52.3.7.1.3
The network mask which, when combined with the corresponding value of ipMRouteSource, identifies the sources for which this entry contains multicast routing information.
Back to PIM-SM-MIB MIB page.
IPHost Network monitor allows you to monitor swPimIpMRouteSourceMask 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.