Forescout vs. Cisco ISE (Identity Services Engine)
Visibility and control beyond the authentication path.
The challenge isn’t controlling the devices you know about. It’s finding and governing the ones you don’t. Cisco ISE is built around authentication. Forescout is built around visibility. That difference determines what each platform can see, assess, and control – long before a policy decision is made.
Authentication controls access. Visibility governs the environment.
Less time guessing. More time in control.
When organizations deploy Forescout, the operational impact is measurable – not just in security outcomes, but in the time and effort it takes to understand and govern the network (or every connected asset).
35 days → 6 min
to discover unknown devices, vs. weeks of point-in-time scans
Visibility in minutes
50%
of IoT devices were unknown before Forescout took inventory
Visibility across unmanaged devices
1.8 hours
to implement policy, down from 125 staff hours
Faster, lower-effort rollout
Source: Nemertes “Forescout Value Realization (REV)” Study, based on customer interviews and analysis (2026)
Why Customers Choose Forescout Over Cisco ISE
Cisco ISE is a mature NAC platform built around authentication. But as unmanaged devices, IoT, OT, and mixed-vendor infrastructure expand, organizations increasingly need visibility, context, and control beyond what authentication alone can provide.
Close Visibility Gaps Across the Entire Environment
Forescout identifies devices the moment they connect – regardless of whether they authenticate, run an agent, or belong to a managed segment. This includes headless IoT and OT assets and devices on misconfigured ports that authentication-based approaches miss.
Visibility reflects the environment as it actually exists – not just the subset of devices that successfully authenticate.
Make Better Decisions with Complete Asset Context
Forescout enriches every connected asset with identity, behavior, connection, risk, and operational context — enabling more precise policy decisions with fewer manual exceptions.
Sharper policies, fewer exceptions, and less time lost to incomplete or misclassified data.
Focus on What is Actually Exposed
Forescout surfaces where connected assets create real exposure – open services, risky communications, vulnerabilities, and control gaps; risk is prioritized based on what is actually reachable and exploitable.
Focus on the exposures that can actually be exploited – not just the risks inferred from identity or posture data.
Evolve Policy Without Breaking Production
Forescout separates visibility and assessment from enforcement, enabling teams to safely test, validate, and refine policies before applying them in production – without risking disruption.
Reduce operational risk while accelerating policy rollout
Extend Control Across Existing Infrastructure
Forescout is vendor-agnostic, delivering consistent visibility, assessment, and control across Cisco, non-Cisco, and mixed environments – without requiring infrastructure standardization.
Security stays consistent across vendors, sites, and device types as the environment evolves.
Expand Control without Expanding Complexity
Forescout helps organizations expand visibility, assessment, segmentation, and control without adding licensing tiers or operational complexity.
More control, more predictable costs, and less administrative overhead.
Forescout Outscores ISE Where it Counts
Forescout consistently outscores Cisco ISE on the factors that determine how quickly organizations realize value: deployment speed, ease of use, and coverage.
Frequently Asked Questions
What is the difference between Forescout and Cisco ISE?
The difference is architectural. Cisco ISE is built around identity-driven network access control (NAC), using authentication, profiling, and policy enforcement to govern access.
Forescout is built around continuous asset visibility, classification, risk assessment, and control across managed and unmanaged devices. As organizations add IoT, OT, IoMT, medical devices, and other connected assets, many choose Forescout to extend visibility, risk assessment, and control beyond traditional authentication-based NAC.
What challenges lead organizations to replace Cisco ISE?
Organizations commonly evaluate replacing Cisco ISE when authentication-based access control no longer provides sufficient coverage for their environment.
Common drivers include:
- Growing populations of unmanaged devices
- Expanding IoT, OT, IoMT, and medical device deployments
- Limited visibility into non-authenticating assets
- Mixed-vendor infrastructure
- Incomplete 802.1X deployment
- The need for continuous asset visibility and risk assessment
- The need to extend policy and control beyond traditional NAC workflows
In these environments, organizations often determine that broader visibility and governance across all connected assets is a higher priority than relying primarily on authentication as the foundation for security.
Is authentication-based NAC enough to secure a modern enterprise network?
Not by itself.
Modern environments include unmanaged devices, IoT, OT, IoMT, medical devices, third-party assets, and remote infrastructure that may not authenticate consistently – or at all.
Authentication remains important, but it does not provide complete visibility across the connected environment. Forescout helps organizations discover, assess, and govern assets beyond traditional authentication workflows.
Can Forescout see devices that Cisco ISE cannot?
In many environments, yes.
Many connected assets – including IoT devices, OT systems, medical equipment, industrial controllers, building systems, and third-party devices—do not reliably participate in authentication workflows, cannot run endpoint agents, or may not support 802.1X.
Forescout uses agentless discovery, passive monitoring, network telemetry, and protocol-aware classification to identify and assess these assets regardless of authentication status, helping reduce blind spots and improve asset visibility.
Does Forescout require 802.1X?
No.
Forescout uses agentless discovery, passive monitoring, network telemetry, infrastructure integrations, and protocol-aware classification to identify and understand assets across the environment – including unmanaged devices, IoT, OT, IoMT, medical devices, and other systems that may not support authentication.
Where 802.1X is deployed, Forescout can use authentication and identity data as additional context. However, visibility, risk assessment, and control do not depend on successful authentication. As a result, organizations can discover, assess, and govern a broader portion of the connected environment -including assets that fall outside traditional 802.1X workflows.
Is Forescout better than Cisco ISE for IoT, OT, and unmanaged devices?
For many organizations, yes.
IoT, OT, IoMT, medical devices, industrial systems, and building-management technologies often do not support 802.1X authentication, cannot run endpoint agents, and may be sensitive to active scanning. These assets frequently fall outside traditional NAC workflows.
Forescout is designed for these environments. It discovers, classifies, assesses, and governs connected assets using agentless techniques that do not depend on authentication. This provides broader visibility across unmanaged devices, industrial systems, healthcare environments, and other asset classes that can create security blind spots.
Does Forescout support OT and industrial control systems?
Yes. Forescout provides visibility and risk context for OT and industrial environments, including PLCs, RTUs, HMIs, DCSs, industrial sensors, and other cyber-physical systems.
Using passive monitoring and protocol-aware analysis, Forescout helps organizations identify industrial assets, understand communications, improve OT asset inventories, reduce cyber-physical risk, and strengthen security across converged IT and OT environments. Forescout also supports compliance initiatives such as NERC CIP and IEC 62443.
Which platform is better for multi-vendor networks?
For mixed-vendor environments, Forescout is the stronger choice. Forescout is designed to discover, classify, assess, and control connected assets across Cisco, Juniper, Aruba, Palo Alto Networks, Fortinet, and other infrastructure platforms from a single solution.
While Cisco ISE is optimized for Cisco-centric environments, Forescout is designed to operate consistently across mixed-vendor networks without requiring infrastructure standardization. The result is broader visibility, more consistent control, and greater operational flexibility across the connected environment.
Can Forescout replace Cisco ISE?
In many environments, yes. Organizations often evaluate a replacement when they need broader visibility into unmanaged devices, stronger support for IoT and OT environments, more consistent coverage across mixed-vendor infrastructure, or greater visibility beyond authentication-based workflows.
Forescout can provide asset discovery, classification, risk assessment, segmentation, and policy enforcement across a broad range of connected assets. It is particularly valuable when organizations need visibility and control for devices that may not support 802.1X or participate consistently in authentication processes.
Whether replacement is immediate or phased depends on existing authentication and access-control requirements.
Can Forescout and Cisco ISE work together?
Yes. Many organizations deploy Forescout alongside Cisco ISE during evaluation, migration, or long-term coexistence. Forescout can help identify unmanaged, unauthenticated, IoT, and OT assets that may not be fully represented within traditional NAC workflows.
Organizations often begin with visibility and then expand into segmentation, policy enforcement, and automated remediation over time. This phased approach provides broader visibility and a lower-risk path to modernization or migration.
How do organizations migrate from Cisco ISE to Forescout?
Most organizations start with visibility.
A common approach is to deploy Forescout alongside Cisco ISE to establish a comprehensive asset inventory, validate device classification, identify unmanaged devices, and understand where visibility gaps exist.
Key considerations include:
- How much current policy depends on 802.1X, RADIUS, MAB, or AAA workflows?
- Which devices are not fully visible today?
- Where are unmanaged, IoT, OT, or third-party assets creating risk?
- Which tools consume Cisco ISE data today?
- Can enforcement be phased in after visibility and classification are validated?
As confidence grows, organizations can expand into segmentation, policy enforcement, and automated remediation, reducing migration risk while extending visibility and control across a broader range of connected assets.
* Comparison based on publicly available vendor materials as of May 2026. G2 scores reflect verified-reviewer ratings in the Network Access Control category and are subject to change.
** Cisco, Cisco ISE, Identity Services Engine, Cisco Secure Client, pxGrid, and AI Assistant are trademarks of Cisco Systems, Inc. Forescout and VistaroAI are trademarks of Forescout Technologies, Inc.