Security

Hi,

Looking for some help with a CPPM issue.

I've configured ClearPass to forward authentication requests from users whose usernames contain a specific domain to a proxy RADIUS server. This setup had been working fine, but it recently stopped.

On the firewall I can see bidirectional traffic - packets going from CPPM to the proxy server and responses coming back - yet end‑user devices are unable to connect. In ClearPass I consistently get error code 208: No response from home server.

When I checked the Event Viewer, I noticed CPPM has marked the proxy server as down, but the logs don't provide any additional detail.

Has anyone run into this before? Is there a way to troubleshoot more deeply - for example, restart the connection so ClearPass forces a re‑probe of the proxy server, or view more detailed RADIUS logs within ClearPass to understand why it's discarding the responses?

Thanks

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Hi

I have no specific experience for troubleshooting this issue, instead more general advices and checkpoints.

• Restarting services or your ClearPass may be an action to test.
• Verify that the other RADIUS server still exists on the same name/IP address and haven't changed, should be as you can see traffic in the firewall
• Verify that you still have the same public IP address if the other RADIUS server have allow listed your public IP address
• Verify your shared secret with the other RADIUS server
• Contact the administrator of the other RADIUS server, ask if they have any error messages related to traffic from your system
• You have already checked the firewall logs if any traffic from your ClearPass to the other RADIUS server is blocked by your firewall, otherwise this would have been an advice.
• Do a pcap from ClearPass and evaluate the traffic between the two servers. Maybe you can see useful information in the packets.
• Enable DEBUG logging under Administration \ Server Manager \ Log Configuration. I'm not sure if the RADIUS proxy function is within the RADIUS service itself or maybe ClearPass network services. Enable DEBUG for RADIUS Server, Policy Service, ClearPass network services and see if you get any additional information.
• From Administration \ Server Manager \ Server Configuration you can export log files from your server in text form. Export the logs with default setting. You will get a lot of files, and need to search in the files if you find anything interesting related to RADIUS proxy

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Best Regards
Jonas Hammarbäck
MVP Guru, ACEX, ACDX #1600, ACCX #1335, ACX-Network Security
Aranya AB
If you find my answer useful, consider giving kudos and/or mark as solution
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