Networks can get very complicated. You might start with just a few devices connected to a modem and a printer, and at that point, your network is easy to map. However, once you maximize the use of your hardware by implementing virtualization and you start to add on specialized servers for storage and applications, you find it is easy to lose track of all of the paths you have created for your business network.
It is very common to use Cloud-based device discovery services these days and wifi links are also regularly deployed in offices alongside wired networks. So, you are going to need to get all of those hybrid networks documented.
Fortunately, you don’t need to put pen to paper to get your network mapped, and you don’t even need to set up a spreadsheet to record all of your network equipment.
Here is our list of the best network discovery tools and software:
- SolarWinds Network Performance Monitor EDITOR’S CHOICE Offers automatic discovery and mapping of networks, including remote sites, cloud-based services, and wifi systems. The wireless network heat map shows the overlap of wifi signals and dead zones. The map is updated automatically and gives details of why applications and services are performing poorly.
- Atera Network Discovery (FREE TRIAL) A complete remote monitoring and management system aimed at managed service providers (MSPs).
- ManageEngine OpManager (FREE TRIAL) This tool can be installed on Linux or Windows, it has some great mapping options that feed off autodiscovery data.
- Datadog Network Performance Monitoring (FREE TRIAL) A network monitoring tool, based in the cloud, that includes automatic network discovery.
- Site24x7 Network Monitor (FREE TRIAL) A cloud-based service that is integrated into Site24x7 system monitoring packages.
- Paessler PRTG Network Monitor (FREE TRIAL) PRTG monitors servers and applications as well as networks; it uses SNMP to map networks and track changes.
- Nagios XI Has its own network monitoring protocol which aids in network discovery.
- Cacti SNMP-driven network monitoring system that includes an autodiscovery phase; it installs on Unix, Linux, and Windows and is free to use.
- NinjaRMM A cloud-based remote monitoring and management service for use by MSPs that includes SNMP network management and device discovery.
- Zenmap A basic frontend to the NMap network discovery and monitoring tool.
- Spiceworks Ad-supported SNMP-based network monitoring software that includes an auto-discovery function.
- NetBrain Cloud-based paid service with a 14-day free trial, this network monitor includes autodiscovery features and some great mapping options.
- Intermapper Specialist network mapping tool for Windows, Linux, and Mac OS creates the layout of your current network after it searches via SNMP.
The best network discovery tools and software
What should you look for in network discovery tools?
We reviewed the market for network discovery software and analyzed the options based on the following criteria:
- An autodiscovery function that runs constantly or on-demand
- The ability to compile a network asset inventory detailing make, model, and firmware version
- A dashboard screen that gives access to details about each discovered device
- Details on how devices are linked together
- A network topology mapper
- A free trial or a money-back guarantee that creates a no-cost assessment period
- Value for money represented by a package that will save time and money
This list includes an updated list of select tools, so you should be able to find the network discovery software that is right for you by reading through our selection.
Larger organizations that need network management functions and not just a network mapper will be drawn to the SolarWinds Network Performance Monitor. This tool begins by tracing all of the networking equipment that is connected. The installation processes include an automated network discovery scanning phase.
The Network Performance Monitor produces a map of your network, which will make it clear how all of your equipment link together. The map includes links over the internet to remote sites and Cloud-based services, and it also includes wifi systems. The graphical displays of your network that the auto-discovery process of the Network Monitor produces include a wireless network heat map. This is a fantastic network mapping bonus because it shows where wifi signals overlap and where you have dead service zones. The information from the heat map makes it clear where you should place your wifi routers to get full signal coverage all across your premises.
The network map itself gets updated automatically if you add, move, or remove a piece of network equipment. The map draws connections between routers, switches, and endpoints on your network. The map is color-coded displaying overloaded connections in red. It also gives a read-out of the volumes of data that each connection carries.
The Network Performance Monitor includes two other mapping facilities, which also generate network visualizations automatically. These are NetPath and PerfStack. NetPath gives you views on all of the links, detailing all of the devices that data will have to pass through on a journey between two given pieces of equipment. These links even extend over the internet to include Cloud-based services. PerfStack is a handy tool that can explain to you why applications and services are performing badly. This screen shows the ongoing performance graphs for a given application with each of the services supporting it beneath it – the services and hardware that support those underlying layers are also shown in the form of a stack. This will help you identify the root cause of performance issues immediately.
The Network Performance Monitor is a comprehensive monitoring system that will keep adjusting network maps and performance indicators in real-time. It will also alert you when operational metrics move into warning conditions. As a full, live management system, this package doesn’t come cheap. It installs on the Windows Server environment and you can get it on a 30-day free trial.
If you aren’t really in the market for a full network monitoring system and just want a tool that can map your network, then take a look at the SolarWinds Network Topology Mapper. This tool is cheaper than the Network Performance Monitor. It also runs on Windows 10 and Windows Server and you can get a 14-day free trial of it. This tool will draw you a nice, straightforward map of your network, which you can export to Visio.
The Network Topology Mapper gives you a choice of detection methods and it will extend to virtual environments and off-site resources. Each node in the map is an icon that leads to a details screen that shows the type of device and its current status. You can alter the style of network map representation and update node information to add in the names that you use yourself rather than the serial numbers of the devices. You can leave the Network Topology Mapper running to get it to update the network map automatically when you change the hardware on the system.
This tool uses SNMP procedures to discover all devices connected to a network and keep track of topology changes. Specifically, it discovers and maps devices, various performance metrics, link utilization, and wireless coverage. The NPM offers a robust set of tools to help you detect, diagnose, and work through a host of network issues.
Get 30 Day Free Trial: www.solarwinds.com/network-performance-monitor/
OS: Windows Server 2016 & 2019
Atera Network Discovery is part a cloud-based support platform for managed service providers (MSPs). The package includes remote monitoring and management (RMM) functions and professional service automation (PSA) systems. The RMM features of Atera include a network discovery tool.
Network Discovery is particularly important for MSPs. The service company contracts to manage networks for clients. However, many clients starting up an MSP contract do so because they haven’t had much success in managing their own networks. In the case of startups and growing small businesses, it is possible that the client business never had qualified network professionals on site. Commonly, these companies do not know exactly what networking equipment they have on-site.
The absence of an equipment inventory makes it very difficult for the MSP to define the requirements of the client accurately. Without that service scope statement, writing up a contract and allocating the right number of staff to the support agreement is virtually impossible.
The network discovery tool in Atera is very useful as part of the agreement formation process between the MSP and the client. It is also a useful tool to have so that the MSP can spot when a remote client adds on extra equipment that was not part of the original agreement.
The network discovery process in Atera runs during the client onboarding process to create a full system inventory. It then runs continuously to spot when equipment is added or removed. This constant inventory update is an essential requirement for billing. MSPs can log the exact date when any equipment was added, and so they don’t miss out on fees for surreptitiously added devices.
Under the hood, the autodiscovery feature of Atera relies on SNMP procedures, so it runs alongside the network performance monitor that is included in the RMM.
As a cloud-based service, Atera is charged for by subscription. Customers can choose whether to pay monthly or yearly. The annual rate works out cheaper, but all fees have to be paid in advance. Charges are levied per technician, and it is easy to add on new accounts as the business expands. This scalability makes Atera a good choice for startups, independent technicians, and rapidly expanding MSPs.
Atera makes a dashboard available as a front end to its services. This console includes the network equipment inventory as well as live network monitoring statuses, which are shown as graphs and charts. The technician gets access to the console through a web browser, and there is no further software for the MSP to install on its site. However, the system that is being monitored does need agents to be installed on it.
The Atera package is available in three editions: Pro, Growth, and Power. All of these editions include the network discovery feature. You can get a 30-day free trial of Atera to put the service through its paces.
ManageEngine OpManager is an extensive network management system that includes an autodiscovery function. The system performs a network discovery scan of your network for devices during the installation phase, and then keeps rechecking all equipment constantly. The links between each piece of equipment enable OpManager to build network maps.
The maps can be displayed in a range of formats. These include a straightforward Layer 2 map that shows all equipment with straight lines representing the links between them. You can also get OpManager to display a 3D view of your premises, showing the location of each piece of equipment. If you have in-house servers held in racks, you can also get the OpManager interface to show you the position of your servers in the cabinet. Finally, you can switch to a world view that shows an actual geographical map with all of the sites of your business connected together. Although the links drawn on that map do not accurately represent the complexity of all of the internet topology between your sites, it does display performance metrics that represent the average speed of the links between your sites.
OpManager continuously monitors your network equipment, using the Simple Network Management Protocol (SNMP) methodology. This system allows for device agents to report alert conditions back to the controller so you will keep abreast of the statuses of all of your network devices. This constant monitoring catches any changes in the inventory of your network, and it will update the network maps automatically.
OpManager includes a network mapping tool, which enables you to create your own custom maps of your network. The network monitor locates the devices for you and then you can change the representation of the layout to be more compliant with your company’s graphical design standards.
The network monitor can manage virtual environments and it will map those for you. It is also able to track VoIP traffic running over the data network, and it can integrate wifi routers and Cloud-based servers into your network map. OpManager includes network traffic analysis, and you can get traffic flow information both link by link and end-to-end depicted on your network maps.
OpManager is available for Linux and Windows environments. There is a free version of the system, which will allow you to manage up to three devices. You can use the free version to get to know the system, using it as a free trial before you commit to buying the full system. Then, depending on the size of your network, you could upgrade to the Standard, Professional, or Enterprise editions – starting from $245 for 10 devices, $345 for 10 devices, or $11,545 for 250 devices respectively.
Datadog Network Performance Monitoring includes a network discovery feature that tracks down all devices connected to the network, logs them in an inventory, and depicts all of the links between them. This is a cloud-based service and so it isn’t necessary to install any software anywhere on site other than an agent program. The agent gathers information and sends it to the Datadog server where all processing occurs.
The console of the service is accessed through any browser. Being a cloud-based service, the Datadog Network Performance Monitoring module can map local and remote networks and also include internet connections to cloud-based resources.
The network view enables the user to change perspective, selecting to see a single device and all of the connections to it, a complete view of the network, or a focus on the links that run between to endpoints.
The network map is live so it gets redrawn if any devices are moved, added, or removed. The network topology map is interactive and acts as an interface through to details on each device.
The data flows traveling around the network and through each device are also shown on the network map. An examination of a specific device offers details on the data throughput of that piece of equipment and status reports on its performance, shown both in graphical format and as event lists.
Traffic views shown on the network map can be segmented by application, or by endpoint, so it is possible to work out which devices or applications are generating the most traffic. The tool has other options that include the ability to analyze traffic patterns and see where devices and links get overloaded. This is a great tool for capacity planning and forecasting.
The Network Performance Monitoring module of Datadog is charged for on a subscription basis with a rate per host per month and also a cheaper annual rate per host. However, whichever payment cycle is chosen, the whole time period has to be paid upfront. Datadog offers a 15-day free trial of the Network Performance Monitoring module.
Site24x7 is an infrastructure monitoring platform that offers a list of specialized tools. The Network Monitor is integrated into all of the system management packages offered by the service.
The Network Monitor has two elements: a device monitoring tool and a traffic analyzer. The network device monitor is based on SNMP. This strategy has the advantage of locating all of the devices on a network through a status report request. The Site24x7 system acts as the SNMP manager, sending out a request every minute as a broadcast. Any device out on the network will have an SNMP agent installed on it that listens for a request.
SNMP agents send status reports in response to the Site24x7 request. The Site24x7 system involves an agent that is a data collector installed on the monitored system. This collects the SNMP responses and uploads them to the Site24x7 server over encrypted connections for processing.
The collection of responses tells the Site24x7 server exactly what devices are out there on the network and how they are connected. This is the autodiscovery feature in the system and it will replay every time an SNMP request broadcast is performed.
The responses from device agents get written up into a network inventory. The Site24x7 network monitor has a network topology mapper, which instantly creates a map of the network from the network inventory whenever it is accessed. So, the topology map is always up to date.
The other component of the Network Monitor is its traffic analyzer. This works through NetFlow and other device communication protocols to collect live traffic throughput data for each interface on switches and routers. This enables the Network monitor to enhance its device inventory and topology maps with live traffic throughput information per link.
The Network Monitor isn’t available as a standalone service. Instead, it forms part of each of the five monitoring service bundles that Site24x7 offers. These are:
- Website Monitoring
- Site24x7 Infrastructure
- Application Performance Monitor
For example, taking out a subscription to Site24x7 Infrastructure gets you access to the Network Monitor plus server, virtualization, application, and website monitoring tools. You can get a 30-day free trial of Site24x7 Infrastructure.
Paessler PRTG is a combined network device monitor, traffic analyzer, and server status manager. This will keep track of the health and performance of all of your network hardware and supporting devices. The server status monitoring extends to Cloud storage and online application services. Application transaction and resource utilization are also covered, and the monitor extends to the tracking of database transactions that server application execution. PRTG will also cover virtual environments and wifi elements in your network. All of those different types of services take a lot of tracking, and it can be challenging to conceptualize all of the interfaces between different types of systems.
Thankfully, you don’t have to set up this complicated network tracking system yourself. The software installs itself, and one of the setup steps is a network discovery scanning phase that will document and list all of these different types of devices and how they work together. You can opt for an online version of the system, but that still needs an agent to be installed on your system. The PRTG dashboard can assemble maps that represent all of the different elements of your network. You can access maps that show virtualization, wifi performance, VoIP traffic, general network performance by link and end-to-end, and connections over the internet through to the operations of network links and server performance owned and managed by other companies.
Paessler PRTG’s monitoring system keeps gathering data on your system and reporting back live statuses on all of your networking equipment, including server conditions. Any potential problems arising in any part of the system get reported to the console immediately. Those alerts can be customized, so you can specify your combination of errors and warnings that would make you sit up and take notice, rather than getting notified about low ink toner levels or other non-critical maintenance conditions. Those lesser problems don’t have to be discarded because you can direct different types of alerts to different team members.
While all of this monitoring is going on, the network discovery process keeps you in the loop. So, any outages or performance problems get reflected on your various network maps. You don’t need to update the network inventory if you add, remove or move equipment because the monitor spots those changes and updates your network maps.
The PRTG system can be accessed as a Cloud service, or it can be installed on premises – the software will run on Windows 10 and Server environments. The system is available for free to monitor small networks. However, a small system wouldn’t need all of the monitoring tools that are bundled into the PRTG tool; this option would be more useful as a partial install for assessment before getting the system to cover a large network. You can also get a 30-day free trial of PRTG.
You will encounter two types of Nagios monitoring software. These are Nagios Core and Nagios XI. The one you need to consider is Nagios XI. Nagios Core is a free, open-source network management tool. However, it doesn’t have a proper front end with it. There is a Nagios Community made up of Nagios users and you can get interfaces for Nagios Core in the community forum for free from some of those users. However, Nagios XI is Nagios Core with a professional interface included, so you are better off going for that version.
The Nagios XI suite includes an autodiscovery module that will map all of your network for you and compile an inventory list. The mapping feature of Nagios XI has a handy utility, which is that it will replay all of your network’s activity, showing traffic levels on a network map. This means that you can review periods of network congestion and watch as bottlenecks appear. This is an excellent tool for analyzing the system weaknesses because you can examine events over and over again, making sure that you understand exactly what happened.
The monitor will observe and record the status of your network equipment and you will see alerts when failure and warning conditions occur. In addition to showing alerts in the Dashboards, you can get Nagios to notify team members by email or SMS. Those alerts can be directed to different team members according to source and severity. The Dashboard can also be customized, which means that you can give access to different views and controls to different team members. The Dashboard widgets include dials, graphs, histograms, and charts that make data easier to view.
Nagios XI runs on CentOS or Redhat Enterprise Linux version 6 or 7. There is a free version of Nagios XI. This is capable of monitoring small networks. Free Nagios XI is limited to monitoring just seven pieces of equipment. The paid version of the system is available in a Standard Edition and a more expensive Enterprise Edition depending on the size of your network.
Related post: Nagios vs Zabbix
Like most of the tools in this list, Cacti uses the SNMP protocol to monitor network devices. A significant advantage of the SNMP methodology is that it has network discovery software built-in. This is because all network devices have SNMP agents installed on them, so any monitoring program just has to broadcast a report request on the network to receive notifications from all of the network equipment. This enables an initial network device inventory to be compiled. The polling process of SNMP is re-issued periodically. That means that the equipment list is continuously updated. So, if you add or remove a device, those changes get registered in the inventory automatically.
Cacti is a free, open-source system that was created to provide a front end to the data gathering RDDTools. So, you need to install both of these systems to get network discovery and monitoring. The RDDTool system is also open source and free to use.
The Cacti package includes a set of graph templates. You can customize a user interface by selecting a subset of the graph template pack. You can also create multiple user accounts and assign different sets of graphs to each. The free tool is useful for allowing users to see their own service consumption in leased service scenarios, SaaS provision, storage services, and even internet service provision. The no-cost model means that a vast number of instances of the software won’t force up costs.
Cacti and RDDTools can be installed on Linux, Unix, and Windows.
NinjaRMM provides all of the tools that an MSPs technician group needs in order to support a client’s IT infrastructure. The package includes a live network monitoring system that is based on SNMP.
As SNMP performs regular status polling by broadcasting a report request, it automatically discovers all network devices. Network devices are shipped from the manufacturer with an SNMP agent installed and that agent is programmed to constantly listen for a status request. Therefore, the technician doesn’t have to set up his monitoring tool with a list of expected assets.
Any device out on the network will automatically respond to the status request and these answers inform the network monitor of exactly what devices are out there on the network. The first time the status request and response cycle runs NinjaRMM collates an asset inventory database. This isn’t static because the responses to future requests might reveal that a new device is out there. In that case, the new device gets added to the inventory.
The network discovery tool is just one of the features of the NinjaRMM system. The dashboard also gives access to live traffic flow data with alerts when devices get overloaded. Other features include Syslog monitoring, patch management, and a managed antivirus service.
The NinjaRMM is a cloud-based service and is charged for by subscription with a rate per device. You can a 14-day free trial of NinjaRMM to experience the network discovery feature on any site.
Zenmap is a graphical front end to Nmap. Both Zenmap and Nmap are free to use. Nmap is a security auditing tool, but it can be used for network scanning. Details of each node include the operating system, manufacturer, device type, IP address, hostname, and the status of the ports on the device.
The interface of Zenmap is very basic, and the tool doesn’t have the ongoing network monitoring capabilities of the other tools on this list. However, Nmap has a huge following and the combination of Zenmap and Nmap is widely distributed. These tools will be of use to you to provide ad-hoc system scans and security checks. As Zenmap is free, you won’t have to worry about your budget if you install it in addition to your regular network monitoring tool.
Zenmap and Nmap will install on Windows, Linux, BSD Unix, and Mac OS.
Spiceworks produces a suite of network monitoring tools that can be installed on premises or accessed online. All of the Spiceworks tools are free but ad-supported. ITo get all of your devices logged, you will need to use the Spiceworks Inventory module. If you prefer to install the software, you need to know that it runs on Debian and Ubuntu Linux and also on Windows and Mac OS.
The Inventory tool will search your system and log all of the equipment connected to your network. Not only will it register each piece of equipment, but the facility also gives you operational details of each device. The scan will also log all of the software that you have available. The Inventory tool will keep all of your software up-to-date with the latest versions and install patches when they become available. You will also be able to see which applications are overloading the network and watch data flows that result in service bottlenecks.
You can enhance the visibility of data and switch from list views over to a graphical representation of the network by installing the Spiceworks Network Mapper. This tool uses the information registered by Spiceworks Inventory, so you need that research tool installed before the mapper will work. You will see traffic volumes on the links between devices represented as the thickness of the line representing the link. The map covers Layer 2 (switches) and Layer 3 (routers) devices. The device icons in the map act as links to detail pages, where you can see the status and operating methods of each piece of equipment.
You can generate reports out of the Inventory system that will list devices by type or you can print out graphs of usage. Server details cover disc volumes and usage, memory availability, and CPU use. Other features of the Inventory package link to the Spiceworks Help Desk module. These include the user details for each endpoint and links to your Active Directory implementation to help you manage user authorization. The Inventory system reaches out to other branches of your system to help you inform and monitor all stakeholders.
NetBrain has an excellent network discovery procedure. The software is accessible online but it can penetrate your network to build an inventory of devices. You enter the IP address of a key router on your network, and the NetBrain system crawls out from there to record all of your network devices. The next phase of installation is the automatic creation of a network map. The map provides the interface for other functions available with the NetBrain package.
The network discovery feature of NetBrain keeps monitoring your system and updates automatically when you add or remove devices. The system will log Layer 2 and Layer 3 devices and help you manage their configurations. The Configuration Management tool in NetBrain alerts for unauthorized changes and also keeps the firmware of your network equipment up to date.
The network maps can identify virtual environments so you can see how many VMs (Virtual Machines) are dependent on each server. You can adjust maps on the fly to request a link view or get reports on end-to-end activity on a given path. This insight helps you to identify bottlenecks and also spot ways to re-route traffic away from troubled hardware.
Process automation enables you to set scripts to operate under certain trigger conditions. The automation works through a system, called “runbooks.” These are workflows that include software update tasks and data collection and analysis routines. The analysis functions help you spot intrusion, and it can also assist you in right-sizing your subnets. The NetBrain system can be sampled on a 14-day free trial.
Intermapper is a product of HelpSystems. The tool installs on Linux, Windows, and Mac OS. This tool uses a range of technologies to detect network-connected equipment. These methods include SNMP and Ping. The tool includes an autodiscovery module, which compiles lists of hardware and also creates a map of your system. The discovery process is continuous and so any changes to the resources on the network automatically get reflected in the inventory and on network maps included in the utility.
If you run a WAN, you can export Intermapper data to overlay on Google Maps to show your network on a real map of the world. Those exports can be scripted and periodic, giving you a near live map of your network status around the world.
As the Intermapper system relies on SNMP, constant status monitoring is an integrated part of its processes. This monitoring also extends to the collection of alert messages sent by device agents, so you get notified immediately if there are any problems with your system. Those alerts get shown in the system console and you can also set up the alerting mechanism to get notifications sent to you or another team member by email or SMS.
You can create action scripts that are triggered by alert conditions and get automatic error resolution. The data that Intermapper collects includes device statuses and network traffic flows. Alert conditions include traffic congestion as well as device statuses.
The Intermapper system is available on subscription and there is a free version with monitoring and mapping functions limited to 10 devices. You can get a 30-day free trial of the full paid version.
Selecting a network discovery tool
As you can see from our list, network discovery tools come in all shapes and sizes. The autodiscovery function is a handy setup feature of many network monitoring systems. It is also an essential element of security monitoring software, so you get a lot of choices when you are looking for a way to map your network automatically.
The list that we have compiled includes tools that are suitable for small and medium networks and others that would only really be of interest to large organizations with complicated networks. The size of your network, your budget, and the operating system of your servers are likely to be the three most important selection criteria that will influence your choice of network discovery system.
Do you employ a network discovery tool in your company? Do you use one of the tools that we have listed in this guide or do you have another tool that you could recommend? Leave a message in the Comments section below to let us know about your experiences.
Network Discovery FAQs
What is passive scanning in networking?
Passive scanning is an information gathering task that relies on catching information that is already in circulation on a network rather than actively querying systems and rewriting programs to originate data. Passive scanning is implemented in a number of network management processes including network vulnerability scanning and network discovery.
Which software is best for documentation?
There are many different types of IT systems that need documentation generated. Here is a list of the best software for documenting network topology and a network inventory.
- SolarWinds Network Performance Monitor
- Paessler PRTG Network Monitor
- Atera Network Discovery
- ManageEngine OpManager
- Nagios XI
How do I stop network discovery from turning off?
The phenomenon of network discovery turning off seems to be a particular problem with Windows 10. This pattern of behavior isn’t very common in business network discovery software that runs on Windows Server or Linux. If your PC displays this problem try these steps.
- Restart the computer to make sure the problem isn’t temporary.
- Update your network adapter
- Go to the Device Manager.
- Right click on the entry for your network adapter
- Select Update driver from the context menu
- Reset network settings
- Go to the Network and internet section of Windows settings.
- Click on Status
- Click on Network reset.
- Restart your computer after this process
- Set sharing options in the network connection settings
- Go to the Status section
- Click on Sharing Options
- Activate the Turn on network discovery radio button
- Check your firewall settings and ensure that it isn’t blocking network discovery
- Check your antivirus system to make sure that it isn’t deactivating your network discovery settings
How do I find free IP addresses on my network?
The easiest way to find free IP addresses on your network is to create a Ping loop.
- Open a command line session
- Enter ipconfig on Windows or ifconfig on Linux or Mac OS
- Look for the Default Gateway entry in the results. Write down the first three octets. In the following example, that Default Gateway address is 192.168.0.1, so the first three octets are 192.168.0
- Enter the following text, replacing the example IP address octets with those of your own network:
for /l %i in (1,1,254) do @ping 192.168.0.%i -w 10 -n 1 | find "Reply"
The results of this loop are all the currently used IP addresses on your network. A free IP address would be one that is not in this list but within the same range. So, pick an address that would lie numerically between the gaps in the series of addresses that are in the Ping loop output.
What is network inventory?
The network inventory is a list of all of the devices that you have connected to your network. This includes network devices, such as switches and routers. The list also includes endpoints, such as PCs, printers, and servers. The network inventory can also show details of each device including make and model and possibly operating system version or firmware version.