Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

NAS duplicated authentication attempt

I see the following message in my failed attempt report on ACS 3.2

Can someone tell me what it means?

NAS duplicated authentication attempt

Cisco Employee

Re: NAS duplicated authentication attempt

The error "NAS duplicated authentication attempt"

in the ACS may indicate a digital cert problem or the ACS has a slow external database.

Generally the error message is an indication that the router (or any device) is in the process of authenticating the user and the user's client software is trying to authenticate again. So the router is in the process of authentication for the user and the user is requesting again because the first authentication response has not yet come back.

Hope that helps.



New Member

Re: NAS duplicated authentication attempt

HI, yusuf I need your help:

I have a Wireless Lan platform composed by equipment Access Points Cisco 1100 with ACS 3,1 and CA Microsoft.The security scheme is EAP-TLS (certificates).This architecture was completely functional. The problem took place when replacing the ACS 3,1 by the ACS 3,2 APPLIANCE, for which new certificates they were emitted by the same CA of the infrastructure. The problem appears when a wireless client tries to connect to the wireless network,without obtaining the objective ,being in a state of "trying to authenticate" in networks adapters, in addition the ACS Logs appear the following message "NAS duplicated authentication attempt".

If somebody knows the reason of this problem, can be contacted to my mail (

CreatePlease to create content