Day 142 – Cisco ISE Mastery Training: External RADIUS Proxy for Cloud NAC

[Day 142 ] Cisco ISE Mastery Training: External RADIUS Proxy for Cloud NAC


Table of Contents

Introduction

In modern enterprise networks, security no longer ends at the perimeter. As organizations adopt cloud-based NAC, BYOD, and multi-vendor wireless solutions, a challenge arises: how do you centralize authentication, authorization, and auditing without duplicating identity stores or exposing internal RADIUS infrastructure directly to the internet?

The answer: External RADIUS Proxy. Cisco ISE acts as a policy decision point, while an external RADIUS proxy can forward authentication requests to cloud-based NAC services (or multiple ISE nodes) while preserving security, scalability, and compliance.

In this Article, l will not only configure the external RADIUS proxy, but also validate authentication flows, troubleshoot failures, and implement real-world use cases. By the end, you will be able to design and deploy a hybrid NAC architecture that integrates seamlessly with both on-prem and cloud infrastructure.


Problem Statement

Real-world challenges solved by external RADIUS proxy:

  • Multi-domain authentication: Enterprise networks often have multiple ISE instances or external NAC systems. Centralizing authentication requests avoids misconfigurations.
  • Cloud NAC integration: Directly exposing internal RADIUS servers to cloud endpoints is risky. A proxy provides a secure relay.
  • Scalability & redundancy: Multiple proxies allow failover and load balancing for high availability.
  • Policy consistency: Ensures that authorization policies are applied uniformly across all access points, wired/wireless, and cloud endpoints.
  • Simplified auditing: Centralized logging via ISE ensures compliance without managing multiple endpoints independently.

Solution Overview

Cisco ISE supports RADIUS proxy functionality where it acts as an intermediary:

  • Receives RADIUS requests from network devices (switches, WLCs, VPN).
  • Forwards requests to the appropriate target server (cloud NAC, another ISE, or third-party RADIUS).
  • Maintains attribute integrity, supports multiple authentication methods, and allows per-request routing based on policies (source IP, NAS ID, user attributes).
  • Provides GUI & CLI tools for monitoring and validation, including Live Logs, Authentication Reports, and debugging commands.

Sample Lab Topology

Topology for VMware/EVE-NG Lab:

DeviceIP AddressRole
ISE Primary Node (VM)10.50.1.10RADIUS proxy configuration
ISE Secondary Node10.50.1.11HA / backend authentication server
Cloud NAC (simulated)10.50.2.20RADIUS target
WLC (VM/Physical)10.50.1.20Wi-Fi Controller, forwards 802.1X requests
Access Switch10.50.1.5802.1X wired client
EndpointsDHCP 10.50.1.xTest clients for authentication
Admin Workstation10.50.1.100For GUI, CLI, Postman/curl testing

Diagram:


Step‑by‑Step GUI Configuration Guide

A – Configure RADIUS Target for Cloud NAC

Step 1: Login to ISE Admin GUI → Administration → Network Resources → Network Devices / RADIUS Targets

Step 2: Click Add → RADIUS Server

  • Name: CloudNAC-Radius
  • IP Address: 10.50.2.20
  • Authentication Port: 1812
  • Accounting Port: 1813
  • Shared Secret: CloudSecret123
  • Retry / Timeout: 3 retries, 5s timeout
  • Check Enabled

[Screenshot placeholder: ISE RADIUS Target Configuration Screen]

Step 3 – Validate RADIUS Target:

  • GUI: Test Connection button
  • CLI:
ping 10.50.2.20
show radius server group CloudNAC-Radius
  • Expected Result: Ping successful, RADIUS server group displayed.

B – Configure Network Device (WLC / Switch) in ISE

Step 1: Administration → Network Resources → Network Devices → Add

  • Name: WLC-01
  • IP Address: 10.50.1.20
  • Device Type: Wireless LAN Controller
  • Shared Secret: WLCSecret123

[Screenshot placeholder: Network Device Add Screen]

Step 2 – Assign RADIUS Target:

  • Under RADIUS Authentication: Select Proxy to CloudNAC-Radius

Step 3 – Validate:

  • GUI: Operations → RADIUS Live Logs → Test Authentication
  • CLI:
debug radius authentication
show radius statistics
  • Expected Result: Incoming request from NAS seen, forwarded to cloud NAC.

C – Configure Policy Set for RADIUS Proxy

Step 1: Policy → Policy Sets → Add New Policy Set

  • Name: Cloud NAC Proxy Policy
  • Condition: NAS-IP = 10.50.1.20 (WLC IP)

Step 2 – Authentication Policy:

  • Select Use RADIUS Proxy
  • Target: CloudNAC-Radius

Step 3 – Authorization Policy:

  • Map attributes returned by Cloud NAC → ISE Authorization Profile
  • Example: CloudNAC-Guest → Guest-VLAN-100

[Screenshot placeholder: Policy Set Authentication & Authorization Screen]

Step 4 – Validate:

  • GUI: Connect test client → Operations → RADIUS Live Logs
  • CLI:
show authentication sessions
show radius statistics
  • Expected Result: Proxy target correctly used, Access-Accept returned, correct VLAN/ACL applied.

D – Configure Backup / Failover RADIUS Target (Optional)

Step 1: Add secondary RADIUS Target → CloudNAC-Secondary

  • IP Address: 10.50.2.21
  • Ports, Secret, Retry/Timeout same as primary

Step 2: Add both targets to RADIUS Target Group

  • Primary = CloudNAC-Radius, Secondary = CloudNAC-Secondary

Step 3 – Configure Policy Set

  • Authentication → Use Target Group
  • Ensure failover order is correct

Step 4 – Validate Failover:

  • GUI: Disconnect primary NAC, authenticate test client → Operations → RADIUS Live Logs
  • CLI:
debug radius authentication
show radius statistics
  • Expected Result: Requests forwarded to secondary, Access-Accept returned.

E – Test End-to-End Client Authentication

  1. Connect test laptop/mobile to Guest SSID.
  2. Observe redirect (if cloud NAC uses captive portal).
  3. Validate in GUI: Operations → RADIUS Live Logs
    • Field: Proxy Target = CloudNAC-Radius
  4. CLI validation:
show authentication sessions
debug radius authentication
show radius statistics
  1. Confirm Authorization Profile applied correctly (VLAN, ACL, ACL download).

F – CLI Quick Reference Commands for Validation

PurposeCLI Command
View RADIUS server groupshow radius server group
Ping RADIUS targetping <IP>
Show authentication sessionsshow authentication sessions
Debug authenticationdebug radius authentication
Show RADIUS statisticsshow radius statistics
Check running config for proxyshow running-config radius

This section is full step-by-step GUI + CLI guide, includes:

  • RADIUS target config
  • Network device setup
  • Policy set creation
  • Failover / backup target setup
  • End-to-end validation
  • CLI quick commands for real-time troubleshooting

Troubleshooting & Diagnostics – External RADIUS Proxy for Cloud NAC

1. Verify Network Connectivity

Objective: Ensure that the ISE proxy can reach the cloud NAC RADIUS server.

Step-by-Step:

  1. Ping the Cloud NAC Targetping 10.50.2.20
    • Expected Result: Successful ping → network reachable.
  2. Traceroute to verify pathtraceroute 10.50.2.20
    • Validate there are no firewalls or NAT devices blocking RADIUS ports (1812/1813).
  3. GUI Check:
    • ISE → Administration → Network Resources → RADIUS Targets → Test Connection

Common Issues:

  • Firewall blocking UDP 1812/1813
  • Incorrect IP address or DNS resolution failure

2. Validate RADIUS Target Configuration

Step-by-Step:

  1. Check RADIUS server groupshow radius server group CloudNAC-Radius
    • Validate IP, ports, shared secret, retry/timeout.
  2. Check Target Enabled Status
    • GUI: Administration → Network Resources → RADIUS Targets → Status column should show Enabled

Common Issues:

  • Disabled target
  • Mismatched shared secret → Access-Reject

3. Check Policy Set Mapping

Objective: Ensure authentication requests match the correct policy set.

Step-by-Step:

  1. GUI: Policy → Policy Sets → Verify conditions
    • NAS IP / Device IP matches WLC/Switch
    • Authentication policy → Forward to RADIUS Proxy
  2. CLI: Validate active sessions: show authentication sessions
    • Check Policy Set Name → must match expected policy

Common Issues:

  • NAS IP mismatch → request routed to default policy
  • Incorrect conditions → fallback to internal authentication

4. Debug RADIUS Authentication

Objective: See live authentication traffic and proxy behavior.

Step-by-Step:

  1. Enable debug: debug radius authentication
  2. Initiate test authentication from endpoint
  3. Observe logs:
    • Look for Proxy Target = CloudNAC-Radius
    • Check Access-Accept / Access-Reject messages
  4. GUI: Operations → RADIUS Live Logs
    • Fields to verify: NAS IP, User, Proxy Target, Authorization Profile

Common Issues:

  • Access-Reject from cloud NAC → check shared secret and authentication method
  • No logs → check NAS forwarding configuration

5. Check Authorization Attributes

Objective: Ensure VLAN / ACL / role is applied correctly.

Step-by-Step:

  1. GUI: Operations → RADIUS Live Logs → Open authentication details
  2. Verify returned attributes:
    • Tunnel-Private-Group-ID → VLAN assignment
    • Filter-Id → ACL applied
  3. CLI: show authentication sessions detail show radius statistics

Common Issues:

  • Attribute mapping misconfigured in ISE → authorization profile not applied
  • Cloud NAC not returning expected RADIUS attributes

6. Failover / Redundancy Troubleshooting

Objective: Ensure secondary RADIUS target is used if primary fails.

Step-by-Step:

  1. Simulate primary failure (shutdown primary cloud NAC or block RADIUS port)
  2. Authenticate test endpoint
  3. Validate logs:
    • GUI: Live Logs → Proxy Target = CloudNAC-Secondary
    • CLI: debug radius authentication → observe failover attempts

Common Issues:

  • Retry / timeout misconfigured → requests drop instead of failover
  • Secondary target not in proxy target group

7. Time / Certificate Validation (SAML / EAP-TLS scenarios)

Objective: Ensure proxy and NAC clocks and certificates are valid.

  1. CLI: Check NTP sync show ntp status
  2. GUI: Verify certificates for EAP-TLS / PEAP if using cloud NAC with certificate-based auth
  3. Test client authentication → validate certificate chain

Common Issues:

  • Clock skew → authentication fails
  • Untrusted certificates → Access-Reject

Advanced Diagnostics

Commands / Tools:

PurposeCLI / Tool
Display RADIUS server group detailsshow radius server group <name>
Live authentication sessionsshow authentication sessions
Debug authentication trafficdebug radius authentication
Show RADIUS statisticsshow radius statistics
Check running configshow running-config radius
Capture SAML / EAP-TLS attributesBrowser SAML-tracer / Wireshark on test endpoint
Test RADIUS reachabilitync -u <IP> 1812 or telnet <IP> 1812

Common Troubleshooting Scenarios

SymptomPossible CauseResolution
Access-RejectShared secret mismatchUpdate secret on ISE and NAC
No RADIUS responseNetwork/firewall issueVerify UDP 1812/1813, routing, NAT
Wrong Authorization Profile appliedCloud NAC returned unexpected attributesUpdate ISE policy mapping
Failover not workingSecondary target misconfiguredAdd to target group, adjust retry/timeout
Client cannot connectNAS not sending RADIUS requests to ISEVerify NAS IP & shared secret

Best Practices for Troubleshooting

  1. Always validate network reachability first (ping/traceroute).
  2. Use Live Logs for GUI confirmation before diving into CLI.
  3. Enable debug radius authentication only during testing; disable after.
  4. Maintain consistent shared secrets across all RADIUS clients/targets.
  5. Document NAS IPs, proxy targets, and policy sets for each endpoint to simplify debugging.

Lab Walkthroughs with Validation – External RADIUS Proxy for Cloud NAC

Lab Objective

  • Configure Cisco ISE as a RADIUS Proxy forwarding requests to a Cloud NAC.
  • Validate authentication, authorization, and failover.
  • Map attributes from cloud NAC to ISE Authorization Profiles.
  • Troubleshoot and confirm correct end-to-end behavior.

Lab Devices (VMware/EVE-NG Lab)

DeviceIP AddressRole
ISE Primary Node10.50.1.10RADIUS Proxy / Policy Server
ISE Secondary Node10.50.1.11Backup / Backend Authentication
Cloud NAC10.50.2.20Target RADIUS Server
WLC10.50.1.20Wireless Controller forwarding RADIUS requests
Access Switch10.50.1.5Wired 802.1X switch
Test EndpointDHCP 10.50.1.xLaptop / mobile for authentication test
Admin Workstation10.50.1.100GUI / CLI monitoring

Step 1 – Configure RADIUS Target in ISE

  1. Login to ISE GUI → Administration → Network Resources → RADIUS Targets → Add.
  2. Configure:
    • Name: CloudNAC-Radius
    • IP: 10.50.2.20
    • Auth Port: 1812, Acct Port: 1813
    • Shared Secret: CloudSecret123
    • Retry: 3, Timeout: 5s

Validation:

  • GUI: Click Test Connection → should succeed
  • CLI:
ping 10.50.2.20
show radius server group CloudNAC-Radius

Step 2 – Configure Network Device in ISE

  1. Add WLC / Switch: Administration → Network Resources → Network Devices → Add
  2. IP: 10.50.1.20, Shared Secret: WLCSecret123
  3. Configure device to forward RADIUS requests to ISE

Validation:

  • GUI: Operations → RADIUS Live Logs → see requests from NAS
  • CLI:
debug radius authentication
show radius statistics

Step 3 – Create Policy Set for RADIUS Proxy

  1. Policy → Policy Sets → Add: Cloud NAC Proxy Policy
  2. Condition: NAS IP = WLC IP
  3. Authentication Policy: Forward to CloudNAC-Radius
  4. Authorization Policy: Map Cloud NAC attributes to ISE Authorization Profiles (e.g., VLAN, ACL)

Validation:

  • GUI: Operations → RADIUS Live Logs → Proxy Target = CloudNAC-Radius
  • CLI:
show authentication sessions
show radius statistics
  • Expected: Access-Accept, correct VLAN/ACL applied

Step 4 – Test Authentication with Wired / Wireless Endpoint

  1. Connect test laptop/mobile to SSID / wired port
  2. Observe 802.1X or captive portal authentication flow

Validation:

  • GUI: Operations → RADIUS Live Logs → confirm Proxy Target = CloudNAC-Radius
  • Authorization Profile applied (VLAN / ACL)
  • CLI:
show authentication sessions
debug radius authentication

Step 5 – Test Failover / Redundancy

  1. Add secondary RADIUS Target → CloudNAC-Secondary
  2. Configure Target Group: Primary = CloudNAC-Radius, Secondary = CloudNAC-Secondary
  3. Policy Set → Authentication → Use Target Group
  4. Simulate primary failure (shutdown primary cloud NAC or block 1812/1813)
  5. Authenticate test client

Validation:

  • GUI: Live Logs → Proxy Target = CloudNAC-Secondary
  • CLI: debug radius authentication → observe request forwarded to secondary
  • Expected: Access-Accept returned without user impact

Step 6 – Attribute Mapping Validation

  1. Ensure cloud NAC sends user roles / VLAN / ACL in RADIUS response
  2. ISE Authorization Policy → maps these attributes to Authorization Profiles
  3. Test multiple users/groups

Validation:

  • GUI: Live Logs → check Authorization Profile applied for each user
  • CLI:
show authentication sessions detail
  • Expected: Correct VLAN / ACL assigned per cloud NAC attributes

Step 7 – Troubleshooting Common Scenarios

ScenarioValidation StepsCLI / GUI
Access-RejectCheck shared secret, authentication methoddebug radius authentication, Live Logs
No Proxy ForwardCheck NAS IP / Policy Set matchGUI Policy Set conditions, show authentication sessions
Failover not workingCheck Target Group config, retry / timeoutshow radius server group, Live Logs
Attribute mapping incorrectVerify Cloud NAC attributes and ISE mappingshow authentication sessions detail, Authorization Profile

Step 8 – End-to-End Lab Summary

  1. Client authenticates via NAS → forwarded by ISE Proxy → Cloud NAC
  2. Cloud NAC returns Access-Accept + attributes → ISE applies Authorization Profile
  3. Failover ensures uninterrupted access if primary NAC unavailable
  4. All authentication sessions and authorization decisions logged in GUI & CLI

Checklist for Validation:

  • RADIUS Target connection tested
  • Policy Set conditions verified
  • Proxy forwarding working (Live Logs / CLI)
  • Attribute mapping correct
  • Failover tested
  • End-to-end authentication successful

Expert Level Use Cases – Step-by-Step Mapping + Validation

Use Case 1: BYOD / Guest Wi-Fi Authentication via Cloud NAC

Objective: Authenticate guest/BYOD users using cloud NAC while ISE acts as a secure RADIUS proxy.

Step-by-Step Implementation:

  1. Step 1 – Configure Guest SSID on WLC / Access Switch
    • GUI: WLC → WLANs → Create SSID → Security → 802.1X with RADIUS server pointing to ISE.
    • CLI (WLC): config wlan create 10 GuestSSID config wlan security wpa akm 802.1X 10 enable config wlan radius add 10 10.50.1.10 1812 CloudSecret123
  2. Step 2 – Configure ISE as RADIUS Proxy
    • Administration → Network Resources → RADIUS Targets → Add CloudNAC-Radius
    • Set authentication port 1812, shared secret, retry, timeout.
  3. Step 3 – Configure Policy Set for Guest SSID
    • Policy → Policy Sets → Add → Condition: NAS-IP = WLC IP
    • Authentication Policy: Forward to CloudNAC-Radius
    • Authorization Policy: Map roles returned by Cloud NAC to VLAN or ACL profiles.
  4. Step 4 – Test Endpoint
    • Connect laptop/mobile to GuestSSID.
    • Validation (GUI): ISE → Operations → RADIUS Live Logs → Proxy Target = CloudNAC-Radius
    • Validation (CLI): debug radius authentication show radius statistics show authentication sessions
    • Expected Result: Access-Accept from cloud NAC, VLAN/ACL applied as per returned attributes.

Use Case 2: Multi-Region NAC Integration with ISE Proxy

Objective: Route authentication requests to the nearest cloud NAC based on NAS location for low latency.

Step-by-Step Implementation:

  1. Step 1 – Add Multiple RADIUS Targets in ISE
    • GUI: Administration → Network Resources → RADIUS Targets
    • Target1: CloudNAC-East, Target2: CloudNAC-West
    • Shared secrets & ports configured identically.
  2. Step 2 – Configure Proxy Target Groups
    • Administration → Network Resources → RADIUS Target Groups → Add
    • Group Name: CloudNAC-Regional → Add both targets
    • Set Primary = East, Secondary = West
  3. Step 3 – Policy Set Mapping
    • Policy → Policy Sets → Conditions:
      • NAS-IP range East → Forward to CloudNAC-East
      • NAS-IP range West → Forward to CloudNAC-West
    • Authentication: Use above proxy targets
  4. Step 4 – Validate
    • Connect endpoint from “East” region network
    • GUI: Live Logs → Proxy Target = CloudNAC-East
    • CLI: debug radius authentication show radius statistics
    • Expected Result: Authentication forwarded to regional NAC; Authorization attributes applied.

Use Case 3: High Availability / Failover Scenario

Objective: Ensure authentication continuity if primary cloud NAC is unavailable.

Step-by-Step Implementation:

  1. Step 1 – Configure Secondary RADIUS Target
    • RADIUS Target → Add CloudNAC-Secondary
    • Set retry & timeout
  2. Step 2 – Add to Proxy Target Group
    • Target Group → Primary = CloudNAC-Primary, Secondary = CloudNAC-Secondary
  3. Step 3 – Policy Set
    • Use same Policy Set → Authentication → Forward to CloudNAC-Primary (with fallback to secondary)
  4. Step 4 – Simulate Failover
    • Bring down primary cloud NAC (shutdown or firewall block 1812/1813)
    • Connect test client to SSID
  5. Step 5 – Validation
    • GUI: Operations → RADIUS Live Logs → Proxy Target = CloudNAC-Secondary
    • CLI: debug radius authentication show radius statistics
    • Expected Result: Access-Accept from secondary target; seamless failover without user impact.

Use Case 4: Attribute-Based Authorization from Cloud NAC

Objective: Apply VLAN, ACL, or role policies returned from cloud NAC via RADIUS proxy.

Step-by-Step Implementation:

  1. Step 1 – Create Authorization Profiles in ISE
    • GUI: Policy → Policy Elements → Results → Authorization → Add Profile
    • Example: VLAN 200 for contractors, ACL Guest-ACL for guests
  2. Step 2 – Policy Set Mapping
    • Authorization Policy → Condition: ExternalGroup = CloudNAC-Contractors → Apply VLAN 200
    • Condition: ExternalGroup = CloudNAC-Guests → Apply ACL Guest-ACL
  3. Step 3 – Validate
    • Connect test client belonging to each group
    • GUI: Live Logs → Verify Authorization Profile Applied
    • CLI: show authentication sessions show radius statistics
    • Expected Result: User assigned correct VLAN / ACL based on cloud NAC attributes.

Use Case 5: Guest BYOD with Multi-Factor Authentication (Cloud NAC)

Objective: Cloud NAC enforces MFA for guest devices; ISE proxy forwards attributes.

Step-by-Step Implementation:

  1. Step 1 – Enable MFA on Cloud NAC
    • Cloud Portal → Enable MFA for guest users
  2. Step 2 – Configure ISE Proxy
    • Forward 802.1X requests to Cloud NAC proxy target
  3. Step 3 – Test Authentication
    • Connect client → cloud NAC prompts for MFA
    • After successful MFA, access allowed
  4. Step 4 – Validate
    • GUI: ISE Live Logs → Proxy Target = CloudNAC, Access-Accept
    • CLI: debug radius authentication → see MFA attribute returned

Each use case provides:

  • Step-by-step mapping: NAS → ISE Proxy → Cloud NAC → Authorization
  • Validation: GUI Live Logs, CLI commands, expected outcome
  • Notes: Failover, attribute handling, MFA integration

FAQs – External RADIUS Proxy for Cloud NAC

1. Q: Why use an external RADIUS proxy instead of direct client-to-cloud NAC authentication?

A:

  • Security: Keeps internal ISE/NAC servers hidden from the internet.
  • Policy centralization: ISE enforces consistent policies across multiple NAC targets.
  • Logging & Auditing: Centralized authentication and authorization logging.
  • Scalability: Supports multiple cloud NACs, regions, or backup targets.
  • Validation:
    • GUI: Live Logs → authentication source shows Proxy Target
    • CLI: show authentication sessions, debug radius authentication

2. Q: How do I validate that RADIUS requests are being correctly proxied?

A:

  • GUI: Operations → RADIUS Live Logs → verify Proxy Target = CloudNAC-Radius
  • CLI:
debug radius authentication
show authentication sessions
show radius statistics
  • Expected: Access-Accept returned from cloud NAC, correct attributes applied.

3. Q: What causes “Access-Reject” from cloud NAC through the proxy?

A:

  • Common causes:
    1. Shared secret mismatch
    2. Wrong authentication method (EAP-TLS, PEAP, etc.)
    3. Cloud NAC user not provisioned or group mismatch
  • Validation: Live Logs → check failure reason; CLI: debug radius authentication

4. Q: How can I test failover if the primary cloud NAC is down?

A:

  1. Add secondary RADIUS target in ISE → configure target group with primary/secondary
  2. Block primary (firewall/shutdown)
  3. Authenticate test client
  • Validation: Live Logs → Proxy Target = CloudNAC-Secondary; CLI: debug radius authentication

5. Q: Can I map cloud NAC user attributes to ISE Authorization Profiles?

A:

  • Yes. Example attributes: VLAN assignment, ACLs, role/group info.
  • Steps:
    1. Authorization Policy → Condition: ExternalGroup = CloudNAC-Group
    2. Apply Authorization Profile (VLAN, ACL)
  • Validation: Live Logs → Authorization Profile applied; CLI: show authentication sessions detail

6. Q: How do I troubleshoot “No RADIUS response received” errors?

A:

  • Verify network connectivity (ping/traceroute to cloud NAC)
  • Check firewall/NAT rules for UDP 1812/1813
  • Validate RADIUS Target configuration (IP, ports, shared secret)
  • CLI:
show radius server group CloudNAC-Radius
show running-config radius

7. Q: How do I ensure attribute consistency during failover?

A:

  • Configure identical Authorization Profiles in ISE mapped to both primary and secondary cloud NAC targets
  • Validate: authenticate clients after failover → check VLAN/ACL applied
  • GUI: Live Logs → Authorization Profile field
  • CLI: show authentication sessions detail

8. Q: Can I use ISE RADIUS proxy for both wired and wireless clients?

A:

  • Yes. Configure NAS devices (switches, WLC) → point to ISE → Policy Set uses Proxy Target
  • Validation: Test wired 802.1X + wireless SSID connections → check Live Logs / CLI

9. Q: How do I debug attribute mapping issues when cloud NAC returns unexpected values?

A:

  • Steps:
    1. Capture RADIUS response from cloud NAC (Live Logs → Attributes)
    2. Verify Authorization Policy in ISE maps the correct attribute → Authorization Profile
    3. Adjust policy conditions if necessary
  • CLI:
show authentication sessions detail
debug radius authentication

10. Q: What are best practices for external RADIUS proxy deployment?

A:

  1. Keep shared secrets synchronized across NAS/Ise/cloud NAC
  2. Test connectivity to all targets before production
  3. Use target groups with failover for redundancy
  4. Monitor Live Logs and CLI debug during deployment
  5. Validate attribute mapping for VLANs, ACLs, and roles

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Closing Notes

  • External RADIUS proxy allows secure, scalable, and policy-consistent NAC integration with cloud services.
  • Always validate flows using Live Logs and CLI debugging.
  • Configure failover targets for high availability.
  • Expert use cases include BYOD, guest Wi-Fi, multi-region NAC, and hybrid authentication flows.

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