The System settings page allows you to define important IPAM variables.
- Enable Duplicate Subnets: When disabled, you cannot create a subnet that is a duplicate or overlaps an existing subnet. The status from multiple DHCP server scopes will merge into one subnet, rather than having different subnets for each server's scope.
- Thresholds: Define the Critical and Warning threshold percentage levels for your IP Address space.
- Configuration Details: Allows you to define if Subnet scans are enabled, default scan intervals, default CIDR value and whether you want IPAM to automatically add IP Addresses.
- Visual Settings: Allows you to define how many items are in the left tree pane, network view items, and IP Address view items.
- Personal Settings: When enabled, this will display a notification message when changes are made to a parent subnet, which contains custom roles.
To edit the IPAM System Settings:
- Click Settings in the upper right.
- Click IPAM Settings.
- Click System Settings.
- Edit as needed (Thresholds, Configuration and Visual settings).
- Click Save.
Allowing Duplicate Subnets
The ability to add duplicate subnets is disabled by default. You can enable this in the IPAM Settings page.
There are some specific use cases where duplicate subnets are desirable. Most of those involve using IPAM as a passive address management system. For example, if an MSP has customers on duplicate internal addresses, IPAM would allow you to create the duplicate space and give the subnet a different name. Obviously in this scenario, they are not scanning because the scan would return the same results. If you find the need to have duplicate subnets, the following steps detail how to enable this setting.
To enable duplicate subnets:
- Click IPAM System Settings.
- Check Enable Duplicated Subnets.
- Click Save.
IPAM utilizes a feature called Neighbor Scanning as an additional method of retrieving information. Neighbor Scanning pulls information from the ARP table of neighboring devices when ICMP and SNMP is blocked or disabled.
Neighbor Scanning is disabled by default.
To enable Neighbor Scanning:
- From the Manage Subnets & IP Addresses tab select a subnet
- Click Properties
- Scroll to the bottom of the Subnet Properties window.
- You should see an option that says Disable Neighbor Scanning. This is checked (disabled) by default.
- When you un-check it, additional options will appear where you can add the IP of the neighbor device.
IPAM first checks if the device is capable of SNMP and supports ARP table:
To check whether SNMP is available IPAM uses these OIDs:
- OidSysContact "188.8.131.52.184.108.40.206.0" iso.org.dod.internet.mgmt.mib-2.system.sysContact.0
To check whether the ARP table is available:
- OidIPNetToMediaTable "220.127.116.11.18.104.22.168" iso.org.dod.internet.mgmt.mib-2.ip.ipNetToMediaTable
The IPNetToMediaTable is pulled for client information. If the device supports this table, then IPAM can work with it.