MAB authentication with MAC-Address 00:00:00:00:00:00

Hi all,

 

I've setup my switch / interfaces to do Dot1x with MAB failover in monitoring mode using ClearPass as RADIUS server. However, one client is having issues failing over to MAB. If I check the authentication history logs, I see that this client is not using it's MAC-address to authenticate but instead is reporting 00:00:00:00:00:00:

 

My interface is configured as follows: 

SWITCHNAME(config)#show running-config interface gigabitethernet 1/0/38

no green-mode eee
speed 100
description "NAC Monitoring"
switchport access vlan X
authentication event fail action authorize vlan X
authentication event no-response action authorize vlan X
authentication event server dead action authorize vlan X
dot1x timeout tx-period 5
dot1x max-reauth-req 3
mab
authentication order dot1x mab

 

SWITCHNAME(config)#show authentication clients all

Interface MAC-Address Method Host Mode Control Mode VLAN Assigned Reason
--------- ----------------- ------- ------------------------ ------------ --------------------------
Gi1/0/38 00:00:00:00:00:00 none multi-domain-multi-host auto Guest VLAN (X)

 

Remarkable is; the method is set to none?

Why is the client not reporting with it's MAC-address? What does the 00:00:00:00:00:00 MAC-Address mean?