What Is Network Access Control?

Network Access Control (NAC) is a cybersecurity measure designed to govern and oversee entry to a computer network. Its goal is to allow only authorized and compliant devices to connect – mitigating the risk of potential security vulnerabilities.

NAC enforces security policies, conducts authentication procedures, and assesses the health of devices seeking network access. Through the evaluation of factors like:

  • Device identity
  • User credentials
  • Adherence to security standards

NAC strengthens network security, empowering organizations to uphold control over their network infrastructure.

How Does Network Access Control Work?

We can divide the whole process of network access control into a few easy to understand steps.

So, here’s how it operates:

  1. Device Authentication:
    • When a device attempts to connect to the network, NAC initiates device authentication to verify its identity. This process ensures that only authorized devices gain access.
  2. User Authentication:
    • NAC may also involve user authentication to confirm the identity of the individual attempting to connect. This can include username/password verification or more advanced authentication methods like multi-factor authentication.
  3. Security Policy Evaluation:
    • NAC evaluates the connecting device against predefined security policies. These policies may include criteria such as antivirus software presence, operating system updates, and adherence to specific security standards.
  4. Health Checks:
    • NAC conducts health checks on the device to assess its overall security posture. This includes checking for the latest software updates, patches, and the absence of malware.
  5. Access Decision:
    • Based on the results of authentication, policy evaluation, and health checks, NAC makes an access decision. Authorized and compliant devices are granted access to the network, while non-compliant or unauthorized devices may be restricted or directed to remediation.
  6. Enforcement Mechanisms:
    • NAC utilizes enforcement mechanisms to implement access decisions. This may involve adjusting firewall rules, VLAN assignments, or other network parameters to enforce the defined security policies.
  7. Continuous Monitoring:
    • NAC often includes continuous monitoring of connected devices. If a device’s compliance status changes during its connection (e.g., due to malware detection), NAC can dynamically adjust access privileges or initiate remediation processes.
  8. Logging and Reporting:
    • NAC systems log access events and generate reports. This provides administrators with visibility into network activities, compliance status, and any security incidents that may occur.

The Benefits of Network Access Control

There are tons of benefits of using Network Access Control in your organization. We’ve listed the most essential ones in the table below.

Enhanced SecurityOnly authorized and compliant devices can access the network. Reduces the risk of unauthorized access and potential security breaches.
Policy EnforcementConsistently enforces security policies across the network infrastructure.
Improved VisibilityProvides better visibility into network activities, facilitating quicker detection and response to security incidents.
Isolation of Non-Compliant DevicesStreamlines the identification and isolation of non-compliant or compromised devices, bolstering the network’s resilience against cyber threats.
Access Control FlexibilityProvides flexibility in defining access controls based on user roles, device types, and other criteria.
Guest Network SecurityEnsures secure access for guests and visitors by implementing temporary and restricted network access.
Network EfficiencyImproves network efficiency by optimizing bandwidth usage and reducing potential congestion.

If you struggle with any of these, or looking to add any ‘benefit’ to your network, you should definitely consider implementing network access control.

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The Disadvantages of Network Access Control

While Network Access Control (NAC) offers numerous advantages for network security, it’s essential to also consider the potential challenges and disadvantages:

Complex ImplementationImplementing NAC systems can be complex and may require careful planning, testing, and integration with existing network infrastructure.
Initial CostsThere are upfront costs associated with acquiring and deploying NAC solutions, including hardware, software, and training expenses.
User Experience ImpactStrict access controls may, at times, impact the user experience, leading to potential frustration and productivity issues.
False Positives/NegativesNAC systems may occasionally generate false positives (blocking legitimate users) or false negatives (allowing unauthorized access), requiring careful tuning.
Guest Access ManagementManaging secure guest access while maintaining a seamless user experience can be challenging and requires careful configuration.
Resource ConsumptionNAC solutions can consume network resources, and improper configuration may lead to performance issues.
Over-reliance on TechnologyRelying solely on technology for security can create a false sense of assurance, overlooking the importance of human vigilance and complementary security measures.

When Should You Use Network Access Control?

Now that you know how network access control works, you might be wondering when you should use it – and whether it’s suitable for your organization.

Now here are some of the scenarios where we recommend implementing NAC.

BYOD (Bring Your Own Device) Environments:

Use NAC in environments where employees bring their own devices. It helps ensure that personal devices meet security requirements before connecting to the corporate network, reducing the risk of introducing vulnerabilities.

Healthcare Environments:

In healthcare settings where the security of patient information is crucial, NAC can play a significant role in controlling access to the network, protecting sensitive healthcare data.

Enterprise Networks:

Use NAC in large enterprise networks to enforce security policies consistently. NAC helps manage access across diverse devices and user roles within a complex network infrastructure.

Critical Infrastructure Protection:

For organizations managing critical infrastructure, such as energy or utilities, NAC is essential to maintain the integrity and security of the network.

Educational Institutions:

In educational environments, especially where there’s a mix of student and faculty devices, NAC helps manage network access and secure sensitive academic information.

Supercharge Cybersecurity with Perimeter 81

Network Access Control (NAC) stands as a crucial safeguard, offering unparalleled control and security over organizational networks. 

Implementing NAC is paramount for every business striving to:

  • Protect sensitive data
  • Mitigate evolving cyber threats
  • Maintain regulatory compliance

For a comprehensive and user-friendly solution that seamlessly integrates with your network security strategy, we recommend checking the Perimeter 81’s cutting-edge cybersecurity solution.


What is the difference between firewall and NAC?
While a firewall primarily blocks non-compliant traffic entering or leaving a network based on simple rule sets, Network Access Control (NAC) operates directly on endpoints. NAC provides a more flexible approach, regulating traffic between devices within the network.
Is NAC hardware or software?
Network Access Control (NAC) software empowers IT managers to establish, enforce, manage, and update secure access policies throughout the enterprise perimeter. It particularly emphasizes remote access systems, including mobile devices, web-based apps, and IoT endpoints operating beyond the immediate corporate network. Explore the top 10 network access control software solutions in 2021 in this article.
What is the difference between NAC and VPN?
While VPNs grant remote connectivity and NAC offers in-office compliance checking, they fall short in safeguarding the mobile workforce against advanced attack tactics. These include sophisticated threats like advanced persistent threats, SaaS threats, spear phishing, and identity theft. Legacy solutions, including VPNs and NAC, struggle to eliminate remote access blind spots, lacking deep visibility into application traffic over secure VPNs. Moreover, the integration of NAC with a VPN not only compromises security but also escalates costs, complexity, and management efforts for IT personnel.
What are two main capabilities of a NAC system?
Network Access Control (NAC) solutions empower organizations to govern network access with the following 2 key functionalities:

Policy Lifecycle Management:
Enforces comprehensive policies across all scenarios, eliminating the need for separate products or additional modules.

Profiling and Visibility:
Identifies and profiles users and their devices preemptively, preventing damage from malicious code.

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