IPAM Subnet Monitoring
IPAM Subnet Monitoring
Track IP address usage across all subnets. Monitor available, used, reserved, and transient addresses alongside DNS and SNMP status from a single view.
Overview
Cloudmon's IP Address Management (IPAM) feature provides centralised tracking and monitoring of IP addresses and subnets across the network. Once a subnet is added and scanning is enabled, Cloudmon continuously polls the subnet and tracks which addresses are in use, which are available, and which are showing conflicts or transient activity. DNS and SNMP status are validated for each address, giving teams a complete picture of IP usage without needing to manage spreadsheets or query devices manually.
Navigate to Network → IPAM Subnet to access the feature. The left-hand panel provides four views: Dashboard (the usage summary described below), Discovered Subnets (subnets pending approval from a supernet or router scan), Subnets (all approved, actively scanned subnets), and Search (look up a specific IP address across all subnets).
Adding Subnets and Supernets
Navigate to Network → IPAM Subnet → Subnets and click the Add button. A dropdown offers three options: Add Subnet, Add Supernet, and Add Router.
Add Subnet
The Add Subnet panel is organized into four sections: Monitor Details, Advanced Details, Configuration Details, and Alert Settings.
Monitor Details: basic identification details for this subnet.
| Field | Description |
| Probe* | The Cloudmon probe that will scan this subnet. |
| Display Name* | A name for the subnet as it will appear in Cloudmon. |
| Description | Optional notes about the subnet. |
| Subnet/Network Address* | The IP address of the subnet, for example 192.168.1.0. |
| Subnet Mask* | The subnet mask, for example 255.255.255.0. |
| VLAN Name | Optional VLAN name to associate with this subnet. |
| Location | Physical or logical location of the subnet. |
Advanced Details: discovery mode, lookup, and authentication settings.
| Field | Description |
| Discovery Mode* | Choose whether to discover addresses using Ping, SNMP, or both. Ping is selected by default. |
| DNS Lookup | Enable Forward Lookup, Reverse Lookup, or both for IP-to-hostname resolution. |
Configuration Details: scheduling and organisation tags.
| Field | Description |
| Polling Interval* | How often Cloudmon polls this subnet. |
| Tags | Optional tags for filtering and grouping subnets. |
Alert Settings: configure notification channels for alert triggers.
| Field | Description |
| Alarm Rule | An alarm rule to apply to this subnet. Optional. |
| User Groups | The user groups that should be notified when an alarm is raised for this subnet. |
| Third Party Services | Third-party integrations to notify when an alarm is raised for this subnet. |
Click Save. Cloudmon will begin scanning the subnet immediately.
Add Supernet
A supernet groups multiple subnets under a common network block. Cloudmon divides the supernet into individual subnets based on the desired subnet mask and lists them in the Discovered Subnets page. Subnets must be manually approved before Cloudmon begins scanning them. The Add Supernet panel has a single Monitor Details section:
| Field | Description |
| Probe* | The Cloudmon probe that will manage discovery and polling for the resulting subnets. |
| Display Name* | A name for the supernet as it will appear in Cloudmon. |
| Description | Optional notes about the supernet. |
| Network* | The network IP address for the supernet block. |
| Network Mask* | The main subnet mask for the supernet. |
| Desired Subnet Mask* | The subnet size Cloudmon will divide the supernet into. Must represent a smaller network than the supernet mask, i.e. more bits set to 1. |
Router
The Router option lists SNMP-enabled devices in Cloudmon that have IP forwarding enabled, such as Layer 3 switches, gateways, firewalls, and printers, showing each device's name, hostname, IP, vendor, and model. Selecting a router and triggering subnet discovery causes Cloudmon to find all subnets associated with that device and list them in the Discovered Subnets tab. These must be manually approved before scanning begins.
What Cloudmon Monitors
Without a centralised view of IP address usage, teams often rely on spreadsheets or manual queries to understand which addresses are in use, which are free, and which may be causing conflicts. As networks grow, this becomes error-prone and slow — IP conflicts go undetected, subnets exhaust without warning, and troubleshooting DNS or SNMP issues requires querying multiple systems. IPAM in Cloudmon addresses this by continuously scanning every configured subnet and presenting the full picture in one place.
The IPAM Dashboard gives a visual summary of total subnets and overall IP address usage, broken down into Available, Conflict, Reserved, Transient, and Used counts. A DNS Status Summary chart shows the result of DNS validation across all addresses, categorised as Success, Mismatch, Forward Lookup Failed, Reverse Lookup Failed, and Not Attempted — making it easy to identify whether DNS failures are forward or reverse lookup specific and how widespread they are. A second chart summarises SNMP accessibility across addresses as Accessible or Not Accessible. Top 5 Subnets by Used IPs and Top 5 Subnets by Transient IPs tables highlight the subnets under the most pressure.
The Subnets view shows each subnet with its subnet mask, size, broadcast address, and a breakdown of Available, Used, Transient, Conflict, Reserved, and Total address counts, alongside its Scan Status and the time of the Last Scan. Clicking into a subnet shows the full list of individual IP addresses and their current status.
Alarms
Alarm triggers can be configured per subnet to alert on IP usage thresholds, such as when a subnet reaches a defined percentage of addresses in use. To attach an alarm rule to a subnet, open its Edit panel and select the desired profile from the Alarm Rule field under Alert Settings. Learn more.
Troubleshooting
| Symptom | Likely Cause | Fix |
| Subnet showing no IP data after adding | Scanning has not been enabled, or the probe cannot reach the subnet | Confirm scanning is enabled for the subnet and that the assigned probe can reach the subnet network range |
| Discovered subnets not moving to Subnets page | Subnets in the Discovered Subnets tab have not been approved | Navigate to the Discovered Subnets tab and approve or enable scan for the subnets you want Cloudmon to monitor |
| DNS status showing as failed for addresses | DNS lookup is enabled but the DNS server is unreachable or the address has no DNS record | Verify the DNS server is reachable from the probe and that DNS records exist for the addresses in question. Check the DNS Status Summary chart on the Dashboard to see whether failures are Forward Lookup or Reverse Lookup specific |