NAC Vendors: Cisco ISE vs. Aruba Clearpass

When comparing Aruba ClearPass and Cisco Identity Services Engine (ISE), IT teams face a decision that will affect network security architecture for years. The rise in remote work has driven organizations to adopt BYOD devices like laptops and smartphones, and these devices remain vulnerable to security threats. Robust Network Access Control (NAC) solutions protect against unauthorized access and cyberattacks, but the two market leaders take different approaches.

This comparison examines the key differences between Cisco ISE and Aruba ClearPass to help organizations select the best fit for their infrastructure.

NAC Vendor Features Comparison

Modern NAC solutions require comprehensive certificate management capabilities. Digital certificates have gained prominence as organizations shift from credential-based protections toward more secure alternatives.

Cisco ISE

• Utilizes the Policy Administrative Node (PAN) for certificate management
• Features built-in Certificate Signing Request (CSR) functionality
• Enables Wildcard SAN certificate creation directly within the CSR interface
• Requires mutual trust between root certificates of nodes in the same cluster
• Supports integration with external certificate authorities, though configuration can be complex

Aruba ClearPass

• Uses administrative nodes called “Publisher” for certificate management
• Includes built-in CSR functionality
• Mutual trust between nodes is unnecessary for privilege assignment
• Requires Wildcard SAN certificates to be created using external tools like OpenSSL
• Offers an onboard module for self-service certificate provisioning, but it adds licensing cost

Wildcard SAN Certificates

Both ISE and ClearPass support Wildcard SSL certificates with wildcard characters (*) in domains. However, security experts caution against this approach, as compromised wildcard certificates present significant vulnerabilities and complicate device visibility through false authentication.

Both ISE and Clearpass are pioneers in the field, but they also have drawbacks with access support for certificate management, especially with the Wildcard certificates. Aruba ClearPass faces challenges with certificate deletion during client re-enrollment, potentially creating messy server-client cleanup scenarios that impact end-user experience.

Active Directory (AD) Integration for Aruba ClearPass and Cisco ISE

Active Directory, introduced by Microsoft in the early 2000s, provides centralized network security and data management. Since then, Microsoft has incorporated multiple services under its directory to cover almost all aspects of network authentication. Both solutions integrate with AD, but differently.

Active Directory Domain Services

AD DS serves as the foundation for Windows domain networks, storing user and device credentials centrally.  The success of both Cisco ISE and Aruba ClearPass has a lot to do with their seamless integration with AD DS.

Let’s take a look at how these NACs function with Active Directory.

Cisco ISE:

• Supports multi-joint AD domains with multiple node joining capabilities
• Allows users to define domain subsets for device authentication requirements
• Utilizes Security Identifiers (SID) for managing group and user attributes
• Handles multi-forest AD environments, though each forest requires separate configuration

Aruba ClearPass:

• Does not support joining multiple nodes
• Performs enforcement by assigning designated tasks to users after AD group verification
• Uses bind operations with AD for LDAP credential authentication
• Permits manual rule creation for attribute utilization from any group

Limitations of On-Premise AD

While AD dominated the on-premise era, cloud computing has introduced Microsoft Entra ID (formerly Azure AD) as an alternative. However, Entra ID lacks native support for LDAP, Kerberos, Group Policy Objects, NTLM authentication, WPA2-Enterprise, and 802.1X authentication, limiting its effectiveness for enterprise network access.

Digital certificates offer a solution, supporting cloud migration while enabling WPA2-Enterprise and 802.1X protocols without on-premise infrastructure burden.

How Cisco ISE and Aruba ClearPass User Interfaces Differ

A good user interface (UI) plays a vital role in determining the usability of any NAC solution. The UI enables network administrators to effectively train users and control access within an organization.

Cisco ISE and Aruba Clearpass have both received positive reviews from their customers. We’ll take a look at the two UIs they offer based on customer reviews and our own experience.

Cisco ISE:

• Limited UI support for complex network configurations
• Requires “flexconfig” implementation for unsupported configurations, potentially degrading performance
• Some users report slower performance compared to competitors
• Subsequent versions (ISE 2.0, 2.3, 3.x) have improved but still carry a steep learning curve

 Aruba ClearPass:

• Faster navigation despite a dated appearance
• User-friendly interface with positive reviews on platforms like Capterra
• Features quick links to frequently accessed sections
• Offers superior documentation compared to Cisco, which primarily relies on community forums

RADIUS Server Implementation for Cisco ISE and Aruba ClearPass

RADIUS (Remote Access Dial-in User Service) is a network authentication protocol following AAA protocols (Authentication, Authorization, Accounting). It is integral to WPA2-Enterprise implementations.

Both Cisco ISE and Aruba ClearPass offer on-premise RADIUS capabilities, though both tend to be expensive. The primary challenge involves selecting a RADIUS solution that adapts smoothly to cloud environments while fitting organizational budgets. Neither vendor offers a fully cloud-native RADIUS option, which can complicate hybrid and cloud-first network architectures.

Quick Comparison: Aruba ClearPass vs. Cisco ISE

Feature	Cisco ISE	Aruba ClearPass
Certificate Management	Built-in CSR with Wildcard SAN creation	Built-in CSR; Wildcard SAN requires OpenSSL
AD Integration	Multi-joint AD domains, SID-based	Single-node join, LDAP bind operations
User Interface	Feature-rich but steep learning curve	Simpler navigation, better documentation
RADIUS	On-premise; no cloud-native option	On-premise; no cloud-native option
Licensing	Complex, tiered by feature set	Simpler licensing, per-device model
Cloud Readiness	Limited; primarily on-prem architecture	Limited; on-prem with some cloud hooks
Best Fit	Large enterprises with Cisco infrastructure	Mixed-vendor environments seeking easier management

Final Verdict: Aruba ClearPass vs. Cisco ISE

Both Cisco ISE and Aruba ClearPass perform context-aware security access but are overly reliant on credentials, creating vulnerabilities. Budget-conscious organizations and mid-level enterprises may struggle with installation and maintenance costs from either vendor. And as networks shift toward cloud-first architectures, both platforms face limitations in hybrid environments.

Organizations seeking alternatives should consider solutions that:

• Leverage existing RADIUS infrastructure
• Support digital certificate-based authentication
• Provide seamless onboarding for BYOD and managed devices
• Offer cloud-native architecture with budget-friendly pricing
• Eliminate reliance on shared credentials while maintaining network security

SecureW2 provides cloud-native Public Key Infrastructure (PKI) through JoinNow Dynamic PKI and Cloud RADIUS, modern solutions that can work alongside or replace legacy NAC infrastructure. Certificate-based authentication eliminates credential theft risks while supporting BYOD, managed devices, and cloud identity providers — without the complexity or licensing overhead of traditional NAC platforms. 

Schedule a demo to see how it works.

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Frequently Asked Questions

Is Aruba ClearPass better than Cisco ISE?

It depends on your environment. Aruba ClearPass is generally easier to manage, has better documentation, and works well in mixed-vendor networks. Cisco ISE offers deeper integration with Cisco infrastructure and more granular policy controls for large enterprises. Neither is a clear winner for every use case.

Can Cisco ISE and Aruba ClearPass use digital certificates for authentication?

Both platforms support certificate-based 802.1X authentication with Extensible Authentication Protocol-Transport Layer Security (EAP-TLS). However, each has limitations in certificate lifecycle management. Organizations that want automated certificate enrollment and renewal without the manual overhead often pair these NAC solutions with a dedicated PKI platform.

What is a cloud-native alternative to on-premise NAC?

Cloud-native network authentication platforms deliver RADIUS and PKI as a managed service, removing the need to deploy and maintain on-premise NAC appliances. This approach reduces hardware costs, simplifies certificate management, and supports cloud identity providers like Okta and Microsoft Entra ID out of the box.