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Cisco Bug: CSCta37465 - MAB runs indefinitely, despite received traffic

Last Modified

Mar 02, 2018

Products (1)

  • Cisco Catalyst 6000 Series Switches

Known Affected Releases

12.2(32.8.11)XJC273.8 12.2(33)SXI 12.2(33)SXI1 12.2SXI

Description (partial)


When a Windows XP (SP2) supplicant with expired credentials connects to a switchport configured for dot1x + MAB, authentication starts. Due to the expired credentials, the switch sents out an EAP Request,  the supplicant sends an EAPoL Start, after which the supplicant goes quiet. The switch sends out 3x EAP Requests to the supplicant, sends out an EAP Failure, deletes the authentication session and restarts another session.

Dot1x times out and MAB is enters "running" state and because its in open mode, the PC has network connectivity, with its MAC address known to the switch (mac address table).Conditions:
Only happens when EAP-TLS is configured with expires certificates on the PC.
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