This past monday I had an entire department that couldn't log in. Looking at the event log I see hundreds of Event ID 13 messages:
A RADIUS message was received from the invalid RADIUS client IP address x.x.x.x
(I removed the IP for security reasons)
The IP was of a valid switch. Prior to the Event 13, I get an Event 10:
The name, <SWITCHNAME>, of the RADIUS client, <SWITCHNAME>, could not be resolved. The data is the error code generated by Windows Sockets.
-Gunnar
So it looks to me like name resolution failed in the morning and that in turn is why the Event 13 occured becuase NPS didn't know who the IPs were. I have since changed my RADIUS clients to IP instead of name, but I'd really like to know what caused this. My DNS servers did not fail on Monday.
