Powerful LAN Scanner

Find every device on your network. Know when something goes wrong before your users do.

What Is the Difference Between a LAN Scanner and Continuous LAN Monitoring?

A LAN scan returns a list of what was reachable at that moment: IP addresses, MAC addresses, device types. Five minutes later, something could drop off the network and the list would not reflect it. Continuous LAN monitoring picks up where a scan stops, polling devices on defined intervals and storing everything it collects.

Paessler PRTG handles both: it discovers devices via auto-discovery and keeps monitoring them afterward using ICMP, SNMP, flow protocols (NetFlow/IPFIX/sFlow/jFlow), and TCP service checks. No manual re-runs required. The data keeps coming in across the usual mix of routers, switches, servers, printers, workstations, access points, and IoT gear, across both IPv4 and IPv6.

What PRTG uses to scan and monitor your LAN: ICMP · ARP · SNMP · NetFlow v5/v9 · IPFIX · sFlow v5 · jFlow v5 · TCP port checks · DNS

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PRTG is compatible with all major vendors, products, and systems

From Device Discovery to Full LAN Visibility

See Every Device on Your Network Without Touching a Spreadsheet

You define the IP range. PRTG does the rest.

Auto-discovery scans the subnet, identifies devices, and builds a structured device tree with sensors pre-assigned. No manual IP-by-IP work, no spreadsheet to maintain, no CSV to update every time something changes.

Scans any defined IP range or subnet on demand or on a schedule
Builds a complete device tree of all reachable network devices
Identifies device types automatically and pre-assigns sensor templates
Works across routers, switches, servers, printers, workstations, and more
Covers IPv4 networks; IPv6 devices reachable via ICMP ping

A Scan Tells You What's There. PRTG Tells You What's Happening.

Advanced IP Scanner and nmap do one thing well: they produce a snapshot. The moment the scan finishes, the data starts going stale. Nothing is retained. Nothing runs tomorrow unless you run it again.

PRTG stores everything it collects. Historical records are kept per sensor, so you can track performance over time, spot trends before they become problems, and run reports without manually assembling data from separate scan results.

Retains historical monitoring data for reporting and capacity planning
Sends notifications via email, SMS, or push when thresholds are exceeded
Persistent device records that update automatically, not a one-time snapshot
250+ native sensor types covering availability, traffic, hardware, and services
Exportable reports and dashboards, not just raw scan results

Configure It Once. It Runs Whether You're There or Not.

PRTG runs as a permanent background service and performs scheduled discovery and monitoring tasks automatically. Scheduled re-discovery (hourly, daily, or weekly) checks for newly connected devices and logs them automatically. When a known device stops responding, PRTG sends an alert.

Runs as a permanent Windows background service with no manual launch required
Scheduled re-discovery at hourly, daily, or weekly intervals
Logs newly discovered devices automatically; your inventory stays current without manual review
Sends an alert when known devices go offline or become unreachable
Configurable scanning intervals per subnet or network segment

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PRODUCT OVERVIEW

Know What Your Devices Are Actually Doing

Availability checks confirm a device is reachable. Performance monitoring tells you what it is actually doing. PRTG collects both after discovery, giving you bandwidth consumption, interface errors, service availability, and load data continuously. You can see what is happening on the network, not just confirm that devices are present.

Per-interface bandwidth monitoring across your LAN
Traffic breakdown by protocol type, so you can identify what's consuming capacity
Hardware metrics across discovered devices: CPU load, memory usage, and disk
Service-level checks on TCP ports for every discovered device, verifying that services are active and accepting connections
Real-time data with configurable alert thresholds per metric

Independent LAN Monitoring for Sites That Manage Their Own Network

If your site manages its own network separately from a central IT department, you need monitoring that fits your setup, not one that depends on infrastructure you don't control.

Install a PRTG probe at your location, run discovery locally, and get full LAN visibility feeding into one central dashboard. No VPN dependency. No waiting on anyone.

Remote probes install at any site and scan the local LAN independently
Classic remote probes run on Windows; multi-platform probes extend coverage to Linux systems
Operates across firewalls without requiring inbound connections to the core server
Each site gets its own auto-discovery and device tree
All site data centralized in one PRTG interface for a unified view

How PRTG Scans and Monitors Your Local Network

PRTG doesn't use one method to collect data. It uses several. What each one returns is different, and so are the gaps.

SNMP Monitoring

PRTG polls SNMP-capable devices using SNMPv1, v2c, or v3. What comes back is interface-level data: traffic in and out, error rates, hardware status. For managed switches, routers, and servers, this is the primary monitoring method once discovery has run.

Devices without SNMP support aren't ignored. PRTG can still ping them for availability. They just won't return interface or hardware data.

Flow Data Analysis

SNMP tells you how much traffic is moving. Flow data tells you what it's made of.

PRTG receives flow exports from compatible routers and switches. The NetFlow v5 Sensor, NetFlow v9 Sensor, IPFIX Sensor, sFlow Sensor, and jFlow v5 Sensor each handle their respective format. What you get is a breakdown by protocol, application type, or connection pair.

Packet Sniffing

No flow-capable hardware on a segment? The Packet Sniffer sensor reads headers of packets passing through a local network adapter and sorts traffic by protocol channel. That's it. Payload content is out of scope, it's not a deep packet inspection tool. You get protocol distribution and traffic patterns, nothing about what's inside.

TCP Port Checks

Discovery tells you a device is there. The Port v2 Sensor tells you whether its services are actually running.

It connects to TCP/IP ports on any discovered device and checks whether the service is accepting connections. HTTP, HTTPS, FTP, SSH, any custom port you define. It works at the TCP level, so any TCP-based service is covered.

RDP is handled separately. PRTG has a dedicated RDP (Remote Desktop) Sensor for that. UDP-based services like DNS or RADIUS have their own protocol sensors too.

One thing the Port v2 Sensor doesn't measure: throughput. It tells you whether the port is reachable, not how much data is moving through it.

DNS Resolution

PRTG resolves hostnames for discovered devices, so your device tree shows readable names instead of raw IP addresses. In larger LANs, that matters more than it sounds. When you're working through 200 devices trying to track down the one that just dropped off, navigating by IP alone costs you time. And if you're not keeping a separate inventory that maps addresses to names somewhere, you're working without a map. DNS resolution means your tree reflects how you actually think about your network.

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LAN Scanner vs. LAN Monitor: Where Free Tools Stop and PRTG Starts

capability	Free scanners Free scanners	PRTG PRTG
Device discovery	Free scanners On demand, manual, one-time.	PRTG Automated, scheduled, continuous.
Continuous monitoring	Free scanners No. Scan ends, monitoring ends.	PRTG Yes. Runs as a permanent background service.
Historical data and trends	Free scanners No. Each scan is a fresh start.	PRTG Stored per sensor. Trends and reports included.
Threshold alerting	Free scanners No. You find out when users complain.	PRTG Email, SMS, and push when thresholds are exceeded.
Traffic analysis (NetFlow, SNMP)	Free scanners No. Devices only, no traffic data.	PRTG SNMP, NetFlow, and packet sniffing per interface.
Remote and multi-site LAN coverage	Free scanners No. One subnet, one tool, manually.	PRTG Remote probes per site, all feeding one dashboard.

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“I would recommend PRTG because it has helped us significantly improve service uptime by highlighting important alerts that would otherwise result in a system failure or service disruption if action was not taken. Thanks to PRTG, we can ensure that The Ritz London’s network and IT systems are five-star, just like the hotel.”

Richard Isted, IT Manager

The Ritz London

Ultimately, people do better when they focus on the solution, not the tool. This is the mantra we live by at Skyscanner. Without PRTG, we’d still be spending half a day or more on monitoring our internal tools.

Barry Kelly, Systems Engineer

Skyscanner

Adopting PRTG has been like going from being in the dark to being in the light. Before, we had limited visibility into what was happening in the infrastructure and in the network. Now, however, thanks to the comprehensive dashboard and real-time notifications, we receive constant updates on the status of facilities and services, and our way of working has gone from passive to proactive.

Luca Meneghesso, senior IT infrastructure and security specialist

Banca Profilo

Paessler PRTG Network Monitor licenses & pricing

Choose the PRTG Network Monitor subscription that's best for you.

License Name	Price	License Details	Get started	Pricing Details
PRTG 500	^$200	per month paid annually	Buy now Buy now	Enough to monitor multiple aspects of 50 devices
PRTG 1000	^$358	per month paid annually	Buy now Buy now	Enough to monitor multiple aspects of 100 devices
PRTG 2500	^$742	per month paid annually	Buy now Buy now	Enough to monitor multiple aspects of 250 devices
PRTG 5000	^$1,300	per month paid annually	Buy now Buy now	Enough to monitor multiple aspects of 500 devices
PRTG 10000	^$1,642	per month paid annually	Buy now Buy now	Enough to monitor multiple aspects of 1000 devices

Over 100,000 Customers Worldwide Love Paessler

[H2] XXX: Frequently Asked Questions

Does PRTG support IPv6 network scanning?

Partly. PRTG discovers IPv6 devices via ICMP ping, so availability monitoring works fine. ARP-based MAC address identification is IPv4 only, and that's what drives device type icons and automatic template matching. IPv6-only hosts show up in discovery. They just won't get auto-classified the same way.

Can I limit the scan to a specific subnet or IP range?

That's how auto-discovery works in PRTG. You define the IP range or subnet, and it scans exactly that. Nothing outside what you specify. If you're managing multiple segments, separate discovery tasks can run for different ranges at the same time.

Is PRTG a replacement for nmap or Advanced IP Scanner?

Different tools built for different things. nmap and Advanced IP Scanner give you a snapshot: run them, get a result, done. The moment the scan finishes, the data starts going stale. PRTG discovers devices and then keeps monitoring them. For security-focused port scanning specifically, nmap is still the better choice for that job.

Can PRTG run network scans from the command line?

PRTG is primarily operated via its web UI and mobile apps. For automation and integration, use the REST API rather than a dedicated interactive CLI workflow. For scripted or automated interaction, there's a REST API, but if your workflow specifically needs CLI-based scanning, nmap handles that better.

Does PRTG work as a free network scanner?

There's a free trial with full functionality, auto-discovery and LAN scanning included. After that, a license is required. Worth knowing that PRTG isn't a standalone scanner in the traditional sense. Device discovery is one part of what it does. The rest is continuous monitoring, alerting, and reporting, and free scanning tools don't cover any of that.