pc can't recongnized network is ok after connecting back from another pc

[jerry zhung]

Recently i has very strange problem, a pc (only the user) can not access network and display can't recognized network, but when i  connected to another pc and then back to itself, it is  normal again. it has happened third time regulatly

the following is related refer :

1, switch is 2960g

2, no crc error

3, only user,one account use the pc

switch interface config

----------------------------------------

switchport access vlan

switchport mode access

authentication order mab

authentication port-control auto

mab

dot1x pae authenticator

-------------------------------------

switch log :

%LINEPROTO-5-UPDOWN: Line protocol on Interface, changed state to down

%LINK-3-UPDOWN: Interface, changed state to down

[Marvin Rhoads · Accepted solution]

Since you're using MAB (MAC Authentication Bypass) you should be checking your RADIUS server (ACS or ISE probably) for the settings particular to the port.

MAB is a means of ensuring only a specific device is allowed to connect to a given port or switch.