IT Asset Discovery: How To Find Every Device You Support

IT asset discovery finds every device you're responsible for, including the ones nobody wrote down. A small team combines the lists its tools already keep (RMM agents, device consoles, DHCP and switch tables) with one active agentless scan per network. Then it reconciles the results with its asset list.

We build SherpaDesk, a helpdesk and PSA (professional services automation) a small IT team can run alone. No contract. No implementation project. No dedicated admin.

What Is IT Asset Discovery?

Discovery feeds the inventory: IT asset management "typically involves performing asset discovery and gathering a detailed inventory." The inventory is the record you keep; discovery checks it against the network. Our IT asset inventory guide covers the record.

Security teams use the same words for attack-surface discovery: finding the points "where an attacker can try to enter." This guide covers the devices you support.

Agent Vs Agentless: Where Discovered Devices Come From

An agent is software on the device that reports in. An active agentless scan asks the network: it signals devices and waits for "a response." Passive discovery sends no probes; CIS lists it as a separate safeguard. Console and API exports report what another system already manages. NIST warns that some components "cannot support agents (e.g., IoT devices, sensors)."

As one r/sysadmin member put it, "I like discovering devices and having a manual inventory. In my opinion, they have different goals."

What You Need Before You Start

How To Run IT Asset Discovery, Step By Step

Example throughout: Lakeside Vet, an MSP client with two offices, an RMM, and a 60-row asset list.

1. Pull the lists your tools already keep

   Export the RMM device list, the MDM or Google console, the directory, and each firewall's DHCP leases. CIS asks teams to use DHCP logs to update the inventory "weekly, or more frequently."

   Example: the RMM shows 41 computers; the firewalls hold 72 DHCP leases.

   Common mistake: exporting names only. As one r/sysadmin member advised, "Try to get useful keys out like serial numbers and mac addresses, you'll want these later."

2. Scan each network from inside it

   Whatever asset discovery tools you use, agree the address range with the client. Check that the scan machine reaches each VLAN, run an active agentless scan, and save the result with source and timestamp. CIS recommends active discovery "daily, or more frequently."

   Example: scans at both offices return 18 devices, including two printers, a NAS, and a camera recorder no agent reports.

   Common mistake: assuming the scan sees every switch. One r/sysadmin member warns: "Watch out for hubs or unmanaged switches- they’re tough to find without tracing cables."

3. Group the sightings and confirm each match

   Put every export into one sheet, one row per sighting, with source and timestamp. Within one client, rows sharing a serial or MAC become match candidates. Merge only after confirming both sightings belong to one physical device; doubtful pairs stay separate. NIST asks for no "duplicate accounting of components." The inventory guide has the detailed rules.

   Example: 131 sightings (41 RMM, 72 DHCP, 18 scan) become 78 confirmed devices.

   Common mistake: keying on IP addresses. They can change when a lease expires.

4. Reconcile the list with your asset record

   Sort every device into three buckets: matched, on the record but not seen, or seen but not on the record.

   Example: 56 devices match, four records were not seen, and 22 devices are unknown.

   Common mistake: marking "not seen" devices as missing. A laptop that was off still exists.

5. Work every unknown device to a decision

   Identify it, name an owner, and decide. CIS asks for a weekly process for unauthorized assets: remove the asset, deny it remote access, or "quarantine the asset." A legitimate device gets a record.

   Example: 15 of the 22 are approved staff phones on guest Wi-Fi, moved to a personal list. The printers, NAS, recorder, and a switch get records. Two unidentified devices stay open on tickets, owned by the lead technician, due in seven days.

   Common mistake: leaving unknowns in a spreadsheet tab. A ticket gives each one an owner and a date.

6. Walk what no scan can see

   Visit each site with the list. As one r/sysadmin member put it, "Automated asset discovery is great and all but nothing beats an onsite visit." Our IT asset audit checklist runs the count.

   Example: the walk finds the four unseen records: three spare laptops in a cupboard and a retired PC.

   Common mistake: treating the walk and the scan as either-or. Another member walks first, so "when you do automatic discovery you have a clue if it's accurate."

An Asset Discovery Schedule For A Small Team

CIS sets the pace: active scans daily, DHCP logs and unauthorized assets weekly, and an inventory review "bi-annually, or more frequently." RMM and console syncs run on each source's own settings.

1. Daily
   Scan

   The active agentless scan runs on a schedule.

2. Weekly
   Review new devices

   Check new scan results and DHCP leases, open a ticket per unknown, and close last week's.

3. Monthly
   Reconcile

   Match every export to the asset record and chase "not seen" records with their users.

4. Twice a year
   Walk each site

   Rotate visits so every site gets two.

What To Look For In IT Asset Discovery Tools

Most IT asset discovery tools find devices; the difference is what happens next. Ask these questions before you buy an IT asset discovery tool. For full tracking, see our IT asset management software picks.

Security-focused asset discovery tools add vulnerability data. For an inventory, a small team can skip that layer.

How To Measure It Worked

Track three numbers monthly:

• Unknown devices open at month end.
• Match rate. Supported devices matched to a record, divided by supported devices discovered. Count approved personal devices and still-unknown devices separately.
• Days to close an unknown. From the ticket opening to its decision. CIS asks for a weekly process, so aim for seven days or fewer.

How this works in SherpaDesk

Your discovered devices in the helpdesk

It's a helpdesk and PSA a small IT team can run alone. No contract, 14 days free, no card. If you run NinjaOne, you can sync its devices into Asset Manager, each device role mapped to a category and type. You can also set alert rules that turn NinjaOne alerts into tickets. Schools can sync Chromebooks, Android, and iOS devices from Google Device Manager, with serial number, MAC address, and device ID mapped to asset fields.

Bulk-import assets from the XLSX template, or add them by hand. Each asset has a unique ID and a status, such as active, retired, or missing. An asset auditor assigned to a location verifies its assets or marks them missing. Assets link to tickets.

Base Camp is $45 per agent per month ($40 billed annually); Asset Manager is on High Camp, $55 per agent per month ($50 billed annually). Schools are priced by student enrollment; ask sales for a quote.

Asset Management →

About the author

Patrick Clements Co-founder & CEO, SherpaDesk

Patrick co-founded SherpaDesk and has led it as CEO since 2013. He has worked with IT service providers since 1998, first on network projects for schools and government offices, then on the helpdesk software their technicians use every day.

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