We have ICX6450 and FCX6XX series switches that are configured to do Flex Authentication, we're seeing an issue where the switches are attempting to not only send the host MAC address but the MAC address of the switch along to the Radius server. The hosts are passing authentication and being moved into the proper VLAN, but the switch MAC is failing and spamming log entries about being denied access. Host communication works fine so this is more of an annoyance at the moment. This is happening in an environment that wasn't able to run Flex Auth previously and hasn't been seen in our other environment.
