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New Member

"Unknown NAS" error on Cisco ACS?

We have a wireless setup including a Cisco ACS RADIUS server. I was checking the reports and under "Failed Attempts" , I found a failed attempt of description "Unknows NAS" and NAS IP address which does not belong to our network.

Can someone explain me what does that mean. Normally any user trying to get to our network and barred by network (for wrong password etc) shows up in this area. Additionally the NAS IP address shown in the report is not part of ACS configuration, so how it showed up the RADIUS server.


  • Security and Network Management
Super Bronze

Re: "Unknown NAS" error on Cisco ACS?


Unknown NAS basically means that the ACS has received an authentication request from a device that has not been configured on the ACS.

For example, you would normally add your switches, dial-in boxes, etc to ACS, putting in the shared secret key etc.

If the device that sends an auth request isn't added, the ACS will not respond to the device, and it will log the event.

If it's a device that should use ACS services, then you need to add it to the ACS network configuratin.



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Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
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