Dell_sss,   So for N2048, it does not have the dedicated MGMT port which cannot have a MAC address for the MGMT. It will have the L3 MAC Address which is the MAC the VLAN will use. Not sure if you can register that with NMS system but that MAC can be used when setting a DHCP reservation. All layer-3 interfaces have the same MAC in Dell OS6/9/10.   Hope this helps.    
HelloTo register the Dell Switch NMS system, you need to register the mac address of the management interface. Even if the N2048-ON device does not have an oob port (management interface port), the mac address is resolved from the mac address table.   The N2048-ON management interface mac-address I found is:     N2048-ON(OS6) [IMAGE] In case of N2048-ON device, mac-address is displayed as vlan1 even though there is no management interface.Is the mac address in mac-address-table the management-interface mac-address, not vlan1?      
How to check the management-interface mac-address of a Dell switch?