With OpUtils enabling advanced subnet monitoring, its Subnet List utility retrieves the list of subnets accessible for a given SNMP node.
Click the Settings -> Tools tab
Choose the System Explorer available under Network Monitoring category.
Select the Subnet List from the tree
Enter the IP Address or Host Name from which the available subnets have to be derived.
Enter the SNMP Community String.
Click the Show button.
Check the results. The IP Address, the DNS Name, the Available Subnets, and the corresponding Netmask values are displayed. To view the ping results of the specified device click the IP Address link.
If the tool is unable to retrieve the results, check if the specified device is SNMP enabled. The Subnet List Tool can only retrieve values from SNMP-enabled devices.