Ping Sweep Discovery via Desktop (GUI)

Ping Sweep is a discovery feature of the LightMesh Windows Discovery Agent. The agent sends ICMP Echo (ping) requests to the hosts in the subnets you select, then reports which addresses responded. Reachable hosts have their Last Seen timestamp refreshed in LightMesh and each cycle is recorded as a PING_SWEEP scan, so you can track live IP usage across your network.

The setup runs in this order:

1. In LightMesh — go to Configuration > Discovery and configure which subnets to sweep, how often, and turn Enabled on. Save changes. Then generate an API key at Admin > API Keys and download the Windows installer from Support > Downloads.
2. On Windows — run the installer and paste the API key when prompted. If you skipped the installer prompt, open the agent to set Base URL and API Token on the Configuration page. Then, on the Dashboard, register the service and start ping sweep from the Ping Sweep tab. Once the agent registers, LightMesh automatically applies the settings from step 1.

Prerequisites

On the Windows machine where the agent runs:

• Operating system: 64-bit Windows. Windows Server 2016 or later is recommended for production.
• Permissions: Local administrator rights to install and control the Windows service. Sending ICMP Echo typically requires the elevated service account the agent runs under.
• Network: The agent must reach the target subnets over ICMP. Firewalls, ACLs, or host-based firewalls that drop ICMP Echo will make otherwise-live hosts appear down. Outbound HTTPS from the agent host to your LightMesh URL is also required so results can upload.

Who can configure ping sweep

Sign in to LightMesh as a user with the Owner or Administrator application role. Only those roles can change ping sweep settings (enable/disable, interval, and subnet selection). Other roles can view status but cannot make changes.

1. Configure ping sweep in LightMesh

Go to Configuration > Discovery in the sidebar. The Ping Sweep tab opens with the configuration for a new agent that has not registered yet: Status shows Pending install and the agent name and address are empty.

Follow the three steps in the info box:

1. Add the subnets below that this agent should sweep. Click Add Subnets, search and filter the same way you do on the Subnets screen, check the subnets you want, and add them.
2. Tweak the interval if you want, and turn Enabled on. Available intervals are Every 15 minutes, 30 minutes, 1 hour, 2 hours, 6 hours, or 24 hours.
3. Click Save changes.

After you save, LightMesh confirms with “Ping sweep settings saved. LightMesh will apply them the moment the discovery agent registers.” and swaps the info box for the four install steps you will run next. Status changes to Waiting for install.

LightMesh applies the settings from this screen automatically the moment the agent registers, so it is safe to configure ping sweep before the Windows machine is ready.

2. Install the Windows Discovery Agent

Complete the four steps shown in the install info box:

1. Generate an API key. In LightMesh, go to Admin > API Keys (the info box links there) and generate a new API key. Set Role to Discovery Agent (DHCP, ping sweep & agent sync only) so the key can register the discovery agent and upload ping sweep results without full tenant API access.
2. Download and install the agent. Go to Support > Downloads (the Windows installer link in the info box opens it). On the Windows Discovery Agent card, under Windows installer (.msi), click Download MSI. The same MSI handles both DHCP and ping sweep.
3. Paste the API key. Run the installer on the Windows host and paste the API key from step 1 when prompted. If you skipped the installer prompt, open the agent, go to Configuration, set Base URL to your LightMesh URL under LightMesh API, paste the key into API Token, and click Save changes. The Base URL probe shows OK when the URL and key can reach LightMesh.

4. Start ping sweep. Open the agent’s Dashboard. If the service is not registered yet, click Register Service in the top-right corner (one-time setup, prompts for UAC). Then select the Ping Sweep tab. Until you start it, the tab shows Ping sweep is off. Click Start Ping Sweep.

Once ping sweep is running, the Ping Sweep tab shows Last Sweep, UP Hosts, Waiting to Upload, and Last Synced. Only UP addresses are uploaded. Use Sync now to run one sweep immediately, or Stop Ping Sweep to turn it off without affecting DHCP collection. The sidebar status card shows Ping Sweep: On.

The Ping Sweep settings section on that tab shows the agent’s Discovery Agent ID, which is filled in automatically after the first GraphQL cycle.

Once the agent registers, the Configuration > Discovery page in LightMesh updates automatically. The agent appears with its name and address, Status moves to Awaiting sweep and then to Active after the first successful upload, and the ping sweep settings you saved in step 1 begin to apply on the next cycle.

3. Enable or disable ping sweep per subnet

You can also control ping sweep from an individual subnet. Open a subnet in Network > Subnets, select the IP Addresses tab, and use the ping sweep toggle in the toolbar:

• When the subnet is swept, the toggle is on and reads Discovered by followed by the agent name. Click the agent name to jump to that agent on Configuration > Discovery.
• When it is not swept, the toggle is off and reads Not discovered via ping-sweep. Turn it on to add the subnet to the agent (if you have more than one agent, pick one in the Agent dropdown first), or click Configure to open Configuration > Discovery.

If no discovery agent is installed yet, LightMesh prompts you to configure ping sweep under Configuration > Discovery first. Only Owners and Administrators can change this toggle.

4. Review ping sweep results in LightMesh

After a sweep cycle completes and uploads:

• Hosts that responded to ICMP Echo are marked reachable, and their Last Seen timestamp is refreshed on the subnet’s IP Addresses view. If Last Seen is not visible, add it with Columns.
• Each cycle is recorded as a PING_SWEEP scan, so ping-sourced activity is distinguishable from NMAP or manual entries.
• On the Configuration > Discovery page, Last Synced shows the most recent upload and Last Sweep shows the most recent completed sweep for the selected agent.

Operational notes

• Enable, interval, and subnets are controlled from LightMesh, not the agent. The agent applies what LightMesh sends it on the next cycle.
• Wide subnets are skipped. By default subnets wider than /16 are not swept, to avoid expanding into millions of hosts. Split large ranges if you truly need to sweep them.
• Ping sweep updates Last Seen and scan history; it does not create or delete IP assignments by itself.

Troubleshooting

If ping sweep results do not appear in LightMesh:

1. Confirm the agent shows on Configuration > Discovery with Status of Awaiting sweep or Active. If it stays on Pending install or Waiting for install, the agent has not registered yet — verify Base URL, API Token, and the Register Service step on the Windows host.
2. Confirm Enabled is on and at least one subnet is added under Configuration > Discovery, and that you clicked Save changes.
3. On the agent Dashboard’s Ping Sweep tab, confirm ping sweep is on, then check Last Sweep and UP Hosts. If the sweep runs but zero hosts come back up, ICMP is likely blocked by a firewall between the agent and the targets.
4. Verify the target subnets are IPv4 and narrower than /16; wider subnets are skipped.
5. Check the agent Logs for ping sweep planning messages, skipped-subnet reasons, and upload results. Failed uploads log an actionable summary (DNS, TCP, TLS, proxy, or HTTP 401/403).
6. Confirm the API key is valid, not expired, and uses the Discovery Agent role, and the Base URL connectivity probe on the agent’s Configuration page shows OK.

Once sweeping and upload succeed, each interval refreshes reachable-host state and Last Seen on the IP Addresses views for your selected subnets.