Network Discovery: A Guide to Enhancing IT Infrastructure and Security

What is network discovery?

Network discovery is the process of detecting and inventorying assets in an IT network.

Network discovery is the cornerstone of many IT monitoring, asset management, network mapping, and cybersecurity best practices because it gives administrators visibility into what devices are on their networks. Worded differently, it is a key technique for improving network visibility.

Whether you follow Information Technology Infrastructure v4 Library (ITIL v4) framework IT service management (ITSM) best practices, adhere to ISO 27001, or just want to run a more efficient network, it starts with a quality asset inventory.

Building that inventory with a clipboard and pencil on modern networks is typically impractical. That’s where network discovery tools come in. They perform scans that streamline the process of creating an initial inventory. Then, the data from network discoveries can support creation of configuration management databases (CMDBs), generation of network maps, and reduce the risk created by shadow IT.

Similarly, network discovery is an essential aspect of modern cybersecurity. Network scanners and passive discovery techniques help security professionals detect devices on a network, enumerate open ports, identify services, and understand networks and potential targets for attackers.

The importance of network discovery

Without effective network discovery MSPs and IT departments will likely have blind spots in their network and increased cybersecurity risk due to shadow IT assets and missed security patches.

Comprehensive network visibility

In many ways, network discovery is important because of its relationship to network visibility. The better your information about assets deployed throughout your network, the better you can understand your network, address immediate issues like unpatched servers, and plan for the future (e.g., hardware refreshes for those old managed switches).

Additionally, network discovery directly enables visualizations like network maps and real-time monitoring and alerting with tools like network management system (NMS) and remote monitoring and management (RMM) platforms.

Benefits for businesses of all sizes

Whether you’re a one-person IT department or a large enterprise, network discovery can help you improve overall IT efficiency and performance. For example, with an accurate asset inventory you can identify aging hardware and take a proactive approach to maintenance instead of waiting for the next failure call.

If you are responsible for maintaining complex networks, network discovery is the first step in mapping those networks to help identify issues with the topology and opportunities for network optimizations. Additionally, network discovery can help you detect potentially vulnerable systems and apply patches or compensating controls before a malicious actor can exploit them.

Integration with remote management systems (RMM)

RMM platforms are a staple for MSPs and network discovery is an excellent complement to RMM. For example, with effective network discovery MSPs can help identify gaps in assets on a client’s network compared to assets under management. Then, once those assets are monitored and managed the RMM features can help ensure streamlined IT operations, enable functionality like remote access, and enable reporting for better overall decision making with the context of all the devices in a given network.

How network discovery works

Network discovery processes typically involve a scan that iterates over a network range(s), detects network-connected devices, and provides a record of the assets discovered along with metadata (e.g., version numbers).

Some common protocols and technologies used in network discovery include:

• Internet Control Message Protocol (ICMP)– ICMP is the protocol that enables the popular “ping”, “tracert”, and “traceroute” commands for checking network connectivity and can also enable discovery of devices that respond to ICMP requests.
• Link Layer Discovery Protocol (LLDP)– LLDP is a layer two protocol defined in RFC 4957 supported by a wide range of network devices. It provides a standard way for network devices to share details and help administrators map their network topology.
• DNS-based Service Discovery (DNS-SD) and Multicast DNS (mDNS)- As the names imply, these protocols depend on DNS to enable network discovery. DNS-SD is described in RFC 6763, while RFC 6762 covers mDNS.
• Simple Network Management Protocol (SNMP)- Despite what some smart people at Google suggested back in 2018, SNMP is not dead. In fact, for those of us who aren’t hyperscalers, SNMP remains one of the most popular protocols for network discovery and network management.
• Windows Management Instrumentation (WMI)– WMI, which is Microsoft’s spin on Web-Based Enterprise Management (WBEM), is a useful protocol for discovering and querying Windows hosts.

In practice, an admin’s network discovery software on a LAN is typically either a standalone scanner or a slice of functionality built into a broader network monitoring and management solution. Typically, the network discovery solutions can be grouped into one of two categories: on-prem software that runs on a local server or cloud software that depends on a locally installed agent to perform network scans.

Common issues in network discovery

While network discovery is important, it’s not always easy. For example, default password laws like California Senate Bill 327 have led to a big shift in device default settings. From a cybersecurity perspective, this is great.

However, it can also make running scans that require credentials and SNMP community strings to detect devices harder. That’s because many systems that previously had common configurations, such as a default-enabled SNMP v1 community string of “public,” have changed to adapt to default password laws. As a result, administrators need some knowledge of network devices to run successful credentialed network scans, creating a catch-22 for undiscovered devices.

System settings (e.g., servers configured to not respond to ping) and security appliances designed to detect and block scanning activity can also reduce the effectiveness of network discovery. For example, NIST 800-53 rev 5 (Security and Privacy Controls for Information Systems and Organizations) includes section SC7-16 which is about preventing discovery of specific system components. If a system is configured not to respond to the protocol you use to poll it, that system won’t be detected in your network scan.

Using a variety of network discovery techniques can help overcome these complexities. For example, if an unknown IP address responds to an uncredentialed polling technique (e.g., ping) technicians can investigate further to identify the device and add it to a monitoring system or CMDB. Additionally, log monitoring and passive network monitoring techniques like packet sniffing can help detect devices that may have otherwise gone overlooked.

Additionally, stale data in CMDBs and asset inventories can give administrators a false sense of security. In IT, data goes stale fast. A network discovery run 2-weeks ago isn’t necessarily accurate anymore. To maintain the benefits of network discovery over time, scans should be run regularly to help keep asset information current.

13 best network discovery platforms

There are plenty of different IT and MSP network discovery tools available today. That can make it hard to find the right solution for a given set of requirements. In some cases, a free scanner can do the trick. Case-in-point: I’m a fan of nmap for quick scans with a specific purpose. In other cases, network discovery must be combined with additional monitoring, management, and reporting features to meet business needs.

In the following sections, we’ll look at a wide range of tools that make up our list of best network discovery tools to help you find the right solution for your business.

1. Advanced IP Scanner

A network discovery scan running in Advanced IP Scanner. (Image Source)

If you need a free, easy-to-use Windows-based network discovery tool, Advanced IP Scanner likely has you covered. This simple tool can discover and list basic information about devices on a network.

Key Features: 

• Free
• Simple to use
• Works as a portable executable or can be installed
• Export discovery results to a spreadsheet format (CSV file)

2. Auvik

A network map in Auvik. (Source: Auvik media room | link to .zip)

Auvik is a popular cloud-based network management system that uses on-prem agents known as “collectors” for network discovery and monitoring. In addition to the standard features you’d expect in a commercial network management system, the Auvik platform offers multi-site support and can detect when a network device’s configuration is changed.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Network mapping
• Robust network monitoring and alerting
• Configuration change detection
• Netflow and sFlow support

3. Cacti

Editing a tree view in the Cacti network monitoring tool. (Image source)

Cacit is a popular, free, open-source monitoring and data collection tool focusing on SNMP devices. It supports Windows and Linux systems and many customization options. Its powerful graphing features are based on the open-source RRDtool.

Key Features: 

• Auto-discovery
• Highly customizable
• Free and open source

4. Intermapper

A network discovery running in Intermapper. (Image Source)

As the name implies, Intermapper is an on-premise network mapping tool. Intermapper supports the creation of customizable network maps based on devices it discovers on the network. Users can leverage this tool to create custom network maps and export them for use in tools like Microsoft Visio. Additionally, support for flow protocols can help identify network performance issues that other protocols may miss.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Create and export network maps
• AWS monitoring
• Flow protocol (NetFlow, sFlow, and jFlow) support

5. ManageEngine OpManager

A subnet discovery screen in Management engine OpManager. (Image Source)

OpManger is a popular on-prem network monitoring software that supports multiple protocols and device types. It can automatically discover devices on a network and provides real-time monitoring to detect potential performance issues.

Key Features: 

• Auto-discovery
• Free tier (limited to 3 devices)
• Network maps
• Support for multiple discovery protocols
• Robust network monitoring and alerting

6. Nagios XI

The Nagios logo. (Source: Nagios GitHub repo)

Nagios XI is a popular enterprise-grade IT infrastructure monitoring platform. As part of its large set of monitoring features Nagios has robust network discovery capabilities. The platform supports auto-discovery and multiple discovery protocols.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Highly customizable
• Network maps

7. NetBrain

The NetBrain logo. (Source: NetBrain | Direct Link)

NetBrain is a no-code network automation platform that provides visibility and network discovery functionality as well. NetBrain’s network discovery capabilities use neighbor-walking techniques that start with a seed router. Using a combination of network discovery protocols and manual inputs, Netbrain can build detailed network layer visualizations.

Key Features: 

• Change management
• Security enforcement
• Support for multiple discovery protocols
• Robust network monitoring and alerting
• Digital twin

8. Paessler PRTG Network Monitor<

A network discovery results populating in PRTG. (Image source)

PRTG is a popular on-premises network monitoring tool from Pressler that supports robust network discovery capabilities. PRTG offers a free tier of up to 100 sensors (monitored data points). After devices are discovered, users can benefit from PRTG features such as network monitoring, mapping, and customizable dashboards.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Free tier (100 sensors)
• Customizable maps

9. SolarWinds Network Performance Monitor (NPM)

A SolarWinds NPM Dashboard. (Image Source)

SolarWinds NPM is a popular on-premise network monitoring solution that can scale to monitor thousands of devices. It offers powerful automatic network discovery and scanning capabilities that make it easy for IT to inventory the assets on a network.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Network mapping and visualizations
• Robust network monitoring and alerting

10. SolarWinds Network Topology Mapper (NTA)

(Source: Solarwinds | Direct link)

Another entry from SolarWinds, NTA is an on-premise tool that is primarily intended to build network topology maps and ensure compliance for standards like PCI DSS. Users can leverage this tool to create detailed network maps based on discovery results and auto-detect if a network topology change occurs.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Network mapping
• Change detection

11. Syncro

The IP Scan PowerShell script in Syncro. (Image Source)

Syncro is a popular, easy-to-use, integrated cloud-based MSP software platform. It includes robust RMM features such as real-time monitoring, remote access, and automated patch management. Additionally, Syncro supports SNMP monitoring for monitoring of network gear and devices like printers and uninterruptible power supplies (UPSes). By combining these powerful IT monitoring and management capabilities with PSA features like ticketing and automated billing, Syncro helps address multiple MSP use cases in a single unified platform.

Syncro also supports integrations with a variety of external tools and platforms and a RESTful API to help extend the platform’s functionality. While Syncro is not primarily a network scanner in the same sense as tools like nmap or Advanced IP Scanner, its powerful scripting engine can enable scanning and network discovery within the platform.

Key features:

• Powerful scripting engine
• Remote access
• Ticketing
• Backgrounding tools
• IT Glue integration for asset details
• Reporting
• Automated remediations
• Customizations
• SNMP monitoring
• Free trial 

12. WhatsUp Gold

A network map from a WhatsUp Gold interactive demo. (Image source)

WhatsUp Gold is another powerful network monitoring system that includes network discovery capabilities. In addition to the standard scanning and alerting features you’d expect in a network monitoring tool, this on-prem software supports features like configuration management and policy compliance audits to help IT with change management.

Key Features: 

• Auto-discovery
• Support for multiple discovery protocols
• Network mapping
• Performance baselines
• Robust network monitoring and alerting
• Configuration management

13. Zenmap

A logical network map created with Zenmap. (Image source)

Zenmap is the graphical front-end for the popular nmap port scanning utility. This free and open-source utility can run on Windows, Linux, and macOS. If you’re performing cybersecurity testing or need a quick and powerful way to capture information about a network, Zenmap may be a good choice.

Key Features: 

• Free and open source
• Service detection
• Network maps
• Supports Windows and Linux
• Powerful and flexible commands
• Uses nmap which is popular with cybersecurity professionals

Choosing the right network discovery tool

Now that you have a feel for the different network discovery tools available, let’s look at the decision-making process

Factors to consider

Even if you use a free network discovery tool, it’s still fundamentally a business decision. The complexity of the tool, value, and manual effort involved should all play a part in your chosen solution. The table below breaks down seven critical factors for selecting a tool and questions to ask.

15 tips for selecting a network discovery tool

With key questions to ask in mind, here are 15 tips that can help you make the right choice during the network discovery tool selection process.

Test with a trial version

Try before you buy is one of the best tips for picking a network discovery tool. Research is great, but it is tough to beat trying the solution for yourself. Wherever practical, install and test the tools you’re considering in an environment that serves as a good proxy for how you’ll use the solution in production.

Check for performance and reliability

Think of yourself as a QA tester during your trial. Exercise the tool to ensure that it will meet your performance and reliability requirements. If that isn’t practical, look for specifications and reviews that help you gauge the tools performance and reliability.

Assess compatibility with existing systems

Tool sprawl is one of the biggest productivity drains in IT. Constant context switching between different dashboards and consoles makes for less productive technicians. Evaluate how well a given network discovery tool works with your existing tools and systems to help reduce the burden.

Look for customization and integration capabilities

Every network is different and you may need to customize or extend your network discovery tool to meet your business requirements. In addition to what’s possible, consider how complex integrations and customizations are for a given tool.

Evaluate scalability options

In addition to understanding if a tool can scale to meet your needs, make sure to evaluate what it takes to scale. Cloud platforms will typically abstract a lot of the complexity, but you’ll still need to install local agent software in most cases. For on-premises solutions, the server hardware and maintenance required to scale may add a meaningful maintenance burden to consider.

Check for compliance with industry standards

Network discovery can directly or indirectly relate to a variety of standards. For example, discovering systems that may store payment data is an essential aspect of Payment Card Industry Data Security Standard (PCI DSS) compliance. Defining what assets are in scope for an information security management system (ISMS) is an important part of compliance to ISO 27001. Similarly, following ITIL ITSM best practices related to asset management typically depends on effective network discovery.

Analyze user interface and ease of use

IT pros have to keep up with a lot of information. In addition to considering the maintenance overhead of a given tool, consider the application’s cognitive load and ease of use. In the ideal case, technicians should be able to hit the ground running with little to no training for network discovery use cases.

Consider the range of features offered

Features are great, but don’t worry about getting the most features for your money. Worry about getting the most value for your money. Start with your must-have features and evaluate platforms based on how well they address those use cases.

Prioritize security measures

Network discovery helps enable security best practices like patch management, but you also need to consider the security of the tool itself. Make sure you understand how sensitive data is stored and transmitted. Additionally, for cloud platforms ensure the provider has sound security and disaster recovery practices in place to safeguard your data (check out what we do at Syncro as an example).

Review cost and licensing models

Obviously, free is great. However, in many cases, businesses require a commercial tool to meet network discovery and management needs. In those cases, be sure to consider the cost and pricing model. For example, a solution that charges you per asset effectively penalizes growth while per-technician (for MSPs) or seat (for IT)  pricing tends to be much more scalable.

Seek user and expert reviews

Review platforms like Trust Radius and G2 can provide a wealth of information in the form of real-user feedback. Additionally, check and see what users are saying about a given tool in online forums like Reddit and Spiceworks.

Ensure responsive customer support

See what other users are saying about a platform’s support. Additionally, once you narrow your choices down to a select few options, contact support yourself and see how well they respond to your inquires.

Examine regular update and maintenance policies

This point is particularly important if you’ll be responsible for regular maintenance of a network discovery platform server. If upgrades are complex or frequent, bake that maintenance cost into the overall cost of the solution. Conversely, if you don’t see a vendor regularly updating their product, that could be a red flag about maintenance and support in the long run.

Consider vendor reputation and longevity

A network discovery tool can play an important role in your business. Make sure you trust the provider of that tool in the long run.

Assess reporting and analytics features

Regular measurement and reporting can help teams focus on the metrics that matter. For example, reporting on unpatched assets can help drive security initiatives. Additionally, reporting features can help MSPs demonstrate value and opportunities at quarterly business reviews (QBRs).

Conclusion

Network discovery is the cornerstone of effective IT asset management and network visibility. There’s no one-size-fits-all best network discovery software for every business, but understanding your requirements and business goals can help you find a set of network discovery tools that work for you.

Integrating IT network discovery with other essential IT functions like network monitoring and ticketing can streamline your overall operations. For MSP businesses, those are the exact type of efficiencies that can make your MSP more profitable.

The all-in-one Syncro platform which includes powerful scripting capabilities, integrations for a wide-range of software tools, professional services automation (PSA ) features, and RMM functionality can be a great way to combine asset information, IT automation, and remote management in a single place. If you’d like to see how Syncro can help you improve network management and IT operations, sign up for a free (no credit card required) trial today!