What is Network Access Control (NAC)?

Controlling access to digital resources is a critical IT security capability for organizations. Network access control (NAC) solutions enable IT to authorize or prevent users and devices from accessing resources on the network. NAC plays an important part in delivering least-privilege access to resources that is foundational to Zero Trust Security strategies.

Network access control explained

Network access controls restrict users and devices from reaching resources based on rules established by IT. Much like door locks and security badges keep intruders from accessing physical organizational resources like buildings and offices, network access controls protect networked digital resources from unauthorized access.

Why is network access control important?

  • Security—Network access controls protect resources from tampering and theft by malicious actors. NAC solutions ensure that only users and devices with proper permissions can access the network and networked resources. Furthermore, some NAC solutions can identify subjects that may be participating in an attack and quarantine or block that subject’s access pending further investigation. This functionality can prevent the spread of attacks.
  • Privacy—Organizations are managing greater volumes and varieties of data than ever before. Some of this data is sensitive and/or confidential. Network access control solutions allow organizations to define who, what, when, and how data can be accessed on the network, to reduce risk of breach.
  • Compliance—Regulated organizations often need to comply with data privacy and data protection mandates, such as the General Data Protection Regulation (GDPR), Health Insurance Portability and Accountability Act (HIPAA), and Sarbanes-Oxley (SOX). NAC solutions can help organizations comply with these mandates by restricting access to data, keeping traffic secure and separate, and providing logging and reporting for audits.

How does network access control work?

Network access control is predicated on the concept that different users and devices (subjects) are granted different types of access based on their needs. Granularity refers to the level of detail with which a subject, its needs, and its associated access permissions can be defined and enforced. Highly granular network access controls are a key component of Zero Trust Security approaches that limit a subject’s access to just the resources needed to do their job or fulfill their function.

To protect resources effectively, network access control solutions must provide several inter-related capabilities delivered through a mix of technologies.

Network access control elements

VisibilityKnowing who and what is on the network at any given timePhysical or virtual data collectors; active (NMAP, WMI, SNMP, SSH) and passive (SPAN, DHCP, NetFlow/S-Flow/IPFIX) discovery methods; AI/ML-assisted device profiling; deep packet inspection
AuthenticationAscertaining with confidence that a user or device is who/what it attests to be802.1x authentication; EAP-TLS, RADIUS, TAC-ACS; multi-factor authentication; certificates
Policy definitionDefining rules for users and devices regarding resources they can access, and how resources can be accessedRule-writing tools, which can include contextual parameters like role, device type, authentication method, device health, traffic patterns, location, and time-of-day
AuthorizationDetermining the appropriate rules for the authenticated user or device 
EnforcementAllowing, denying, or revoking an authenticated user or device’s access to a resource based on appropriate policyIntegration and bidirectional communication with firewalls and other security tools

What are examples of network access control?

NAC solutions provide secure access to resources throughout an organization. For example, a hospital uses a NAC solution to profile, secure and manage connectivity of authorized IoT devices, while excluding others. A fulfillment center uses a NAC solution to authenticate every wired and wireless device that accesses the network—such as robots—and implement consistent role-based policies. A school system uses a NAC solution to authenticate students, teachers, staff and guests, and enable granular segmentation of traffic based on defined rules.

Examples of network access control within an enterprise network

What is network access control used for?

NAC solutions like HPE Aruba Networking ClearPass can address several secure connectivity use cases within organizations:

NAC for guests and temporary workers ClearPass Guest makes it easy and efficient for receptionists, event coordinators, and other non-IT staff to create temporary network access accounts for any number of guests per day. ClearPass Guest also offers a customized self-registration portal, which allows visitors to create their own credentials that are then stored in ClearPass for pre‑determined amounts of time and can be set to expire automatically.
NAC for bring your own device (BYOD)ClearPass Onboard automatically configures and provisions mobile devices, enabling them to securely connect to enterprise networks. Workers can self-configure their own devices by following guided registration and connectivity instructions. Unique per-device certificates are applied to ensure that users can securely connect their devices to networks with minimal IT interaction.
NAC for endpoint security posture assessmentClearPass OnGuard performs endpoint/device posture assessment to ensure security and compliance requirements are met prior to devices connecting to the corporate network, which can help organizations avoid introducing vulnerabilities into their IT environments.
NAC for Internet of Things (IoT) devicesClearPass Device Insight provides full spectrum visibility of network-connected devices with risk-scoring and machine learning to identify unknown devices and reduce time-to-identification. ClearPass Device Insight also monitors the behavior of traffic flows for added security.
ClearPass Policy Manager profiles devices trying to connect to the network and provides role- and device-based network access based on rules configured by IT.
NAC for wired devicesClearPass OnConnect provides secure wired access control for devices like printers and VoIP phones that do not authenticate using 802.1x techniques.
Cloud-native NACHPE Aruba Networking Central Cloud Auth integrates with common cloud identity stores to deliver seamless cloud-based onboarding and secure role-based policy for users and devices.

How do I select a network access control solution?

When choosing a NAC solution, consider the following:

  • Interoperability and vendor-neutral features to avoid costly add-ons and vendor lock-in
  • Demonstrated ability to keep traffic secure and separated
  • Service availability to support maximal uptime and non-stop operations
  • Scalability to support hundreds of thousands of concurrent endpoints
  • Market leadership and designations that recognize capability to reduce cyber-risk, such as Cyber CatalystSM by Marsh designation

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