The switch does not receive a response to RADIUS authentication requests

In this case, the switch attempts authentication using the secondary method configured for the type of access you are using (console, Telnet, or SSH).

There can be several reasons for not receiving a response to an authentication request. Do the following:

  • Use ping to ensure that the switch has access to the configured RADIUS server.

  • Verify that the switch is using the correct encryption key for the designated server.

  • Verify that the switch has the correct IP address for the RADIUS server.

  • Ensure that the radius-server timeout period is long enough for network conditions.

  • Verify that the switch is using the same UDP port number as the server.


Because of an inconsistency between the Windows XP 802.1x supplicant timeout value and the switch default timeout value, which is 5, when adding a backup RADIUS server, set the switch radius-server timeout value to 4. Otherwise, the switch may not failover properly to the backup RADIUS server.