Symptom
IE-3200/IE-3300/IE-3400 switch configured to use a RADIUS server for AAA purposes.
If the RADIUS server is reachable over IPv4, then both 802.1x/MAB and VTY/console line authentication are successful against this RADIUS server and there is no issue.
If the RADIUS server is reachable over IPv6, then 802.1x/MAB fails with AAA Server Down reason, but VTY/console line authentication is still successful against this RADIUS server.
In the show aaa servers, this IPv6 RADIUS server is declared DEAD in the "Platform State from SMD" but still shows as UP in the line above.
Conditions
IE-3200/IE-3300/IE-3400 switch
802.1x and MAB authentication for wired clients
IPv6 connectivity between the switch and RADIUS server
Workaround
None other than enabling IPv4 transport or disabling 802.1x/MAB wired client authentication
Further Problem Description
This problem is seen in recent releases such as [but not limited to]:
17.03.06
17.06.04
17.09.02
17.10.01
