Choosing your 802.1X authentication strategy: Certificate vs. identity-based

In today’s dynamic enterprise environments, ensuring secure network access is a critical challenge. Organizations are increasingly required to provide internet access to a diverse range of devices and users, including guests, consultants, Bring Your Own Device (BYOD), and Internet of Things (IoT) devices, all of which may be unmanaged and untrusted. Traditional network security postures, such as shared Wi-Fi passwords, are often insufficient to secure these varied connections, leading to potential vulnerabilities and legal liabilities.

This is where 802.1X and Network Access Control (NAC) become indispensable. 802.1X is the industry standard for Port-Based Network Access Control, designed to authenticate devices as they connect to both wired (LAN) and wireless (WLAN) networks. Rather than relying on a single shared password, 802.1X mandates individual authentication for each user or device, providing a robust solution for centralized, secure network access control. Cloudi-Fi Cloud RADIUS serves as the central system for handling these authentication requests.

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Why 802.1X is essential for modern networks

The core principle behind 802.1X is to prevent a device from accessing the network until its identity has been successfully proven. This approach offers two significant benefits:

• It eliminates the risk associated with compromised shared passwords.

• It enables dynamic access policies, such as Virtual Local Area Network (VLAN) assignment, based on the specific identity of the user or device.

The overall authentication process is managed by a central RADIUS server, which validates credentials against a trusted identity source. Cloudi-Fi Cloud RADIUS acts as this central system, validating credentials against identity providers like certificates or Microsoft Entra ID and subsequently sending access policies upon successful authentication.

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Understanding the 802.1X authentication workflow

The 802.1X authentication sequence follows a clear, multi-step process, regardless of the specific authentication method chosen:

1. Initialization and detection: An authenticator (such as a switch or access point) detects a new device (known as a supplicant) attempting to connect to the network. The authenticator then sets the device's port to "unauthorized," blocking all traffic except for Extensible Authentication Protocol (EAP) packets.

2. Initiation and request: The authenticator sends an EAP-Request to the supplicant, requesting its identity. The supplicant responds with its EAP-Response, exchanging identifying information.

3. Negotiation: The authenticator forwards these EAP requests to the Cloud RADIUS server (Cloudi-Fi Cloud RADIUS). The RADIUS server then challenges the supplicant and selects the appropriate authentication method (e.g., certificate).

4. Authentication: The supplicant provides its credentials (e.g., a digital certificate or corporate login details) to the RADIUS server. The RADIUS server validates these credentials against the configured identity provider.

5. Authorisation and access: Upon successful authentication, the RADIUS server sends a positive response and dynamic access policies (such as VLANs or Access Control Lists) back to the authenticator. The authenticator then opens the network port and applies these specified policies, granting the device network access.

6. Accounting: The RADIUS server logs session details, including the device's MAC address, the port used, and the session duration, for monitoring and auditing purposes.

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Cloudi-Fi's authentication power: certificate vs. identity

Cloudi-Fi Cloud RADIUS supports two primary and highly effective methods for 802.1X authentication, each with distinct advantages and configuration requirements:

Certificate-based authentication (with Cloudi-Fi Cloud RADIUS)

This method leverages digital certificates issued by your corporate Certificate Authority (CA). It’s highly secure and automated, making it ideal for managed corporate devices.

• How it works: The RADIUS server validates the device certificate (signed by your CA), checks revocation, and applies policies based on attributes (e.g., OU, CN).
  
• Key benefit: Passwordless authentication, resistant to phishing and credential theft.
  
• Typical use case: Laptops, desktops, or corporate mobile devices under MDM/Intune.
  
• Setup with Cloudi-Fi (high-level):
  
  1. Add a NAC provider in the Cloudi-Fi console and select Certificate.
     
  2. Upload your CA certificate (PEM/DER format).
     
  3. Map certificate fields (e.g., CN → Identifier, OU → Profile).
     
  4. Save & apply.
     

 For detailed configuration steps, see our Certificate-based 802.1X setup guide.

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Identity-based authentication (Microsoft Entra ID with OAuth2)

This method uses corporate credentials, integrating directly with Microsoft Entra ID. It simplifies authentication for employees and contractors.

• How it works: RADIUS server validates user sign-in against Entra ID, applies group-based policies.
  
• Key benefit: Leverages existing credentials and MFA, no PKI needed.
  
• Typical use case: Consultants, contractors, BYOD users.
  
• Setup with Cloudi-Fi (high-level):
  
  1. Register a new application in Microsoft Entra ID.
  2. Assign necessary API permissions (e.g., User.Read, Group.Read).
  3. Create a client secret and copy IDs/endpoints.
  4. In Cloudi-Fi console, add Entra ID as NAC provider, input details, and test.
  5. Map Entra attributes (e.g., displayName → login, group.displayName → group).
     

 For detailed instructions, see our Entra ID 802.1X integration guide.

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Conclusion

Cloudi-Fi Cloud RADIUS provides enterprises with the flexibility and security needed to implement robust 802.1X Network Access Control. Whether your organisation prioritises the automated, device-centric security of certificate-based authentication or the streamlined user experience and deep integration of identity-based authentication with Microsoft Entra ID, Cloudi-Fi offers the tools to ensure that only authenticated and authorised entities gain access to your network. This granular control not only significantly enhances your security posture but also simplifies global compliance with evolving regulations, making your network both secure and highly adaptable.