With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swDHCPServerDNSServerAddress
Switch DHCP Server DNS Server Address
1.3.6.1.4.1.171.12.38.3.2.2.1.3
The IP address of a DNS server that is available to a DHCP client.
Back to DHCP-Server-MIB MIB page.
IPHost Network monitor allows you to monitor swDHCPServerDNSServerAddress 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 WiFi routers right now.