If the authentication server cannot be reached, the switch can retransmit the
request. If no response is received from the server after the speci?¬?ed number of attempts,
authentication fails, and network access is not granted.
When a client logs out, it sends an EAPOL-logout message, causing the switch port to
transition to the unauthorized state.
NOTE You can ?¬?nd more information on con?¬?guring 802.1X port-based authentication
in the Cisco CCNP curriculum.
76 Chapter 2: Medium-Sized Switched Network Construction
Summary of Securing the Expanded Network
The list that follows summarizes the key points that were discussed in this section.
?– Follow recommended practices for securing your switched topology by using
passwords, deactivating unused ports, con?¬?guring authentication, and using port
security.
?– To secure a switch device, you must secure access to the switch and the protocols that
the switch uses.
Troubleshooting Switched Networks
As the number of switch features grows, so does the possibility that things will go wrong.
This section presents recommendations for implementing a functional network. It also
addresses some of the common reasons that port connectivity, VLAN con?¬?guration, VTP,
and STP can fail, as well as what information to look for to identify the source of a problem.
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