Technical Note: 802.1x connectivity issues due to no RADIUS server response

[FortiKoala]

Description

Clients fail to connect using 802.1x authentication. The following symptoms are experienced:

• Controller logs show RADIUS request being sent to NAC, but no response.
• tcpdump shows RADIUS Access Requests received by NAC, but no Access Accepts or Rejects returned.
• With RadiusManager debug enabled, output.master prints the following error:  RadiusServer failed to contact server <RADIUS Server IP address>

Solution
Verify the User Name and Password defined in the RADIUS Server model in NAC matches the account created in the RADIUS Server itself.     

In the NAC administration UI, navigate to System > Settings > RADIUS.
Highlight the RADIUS Server model and click the Modify button.