Configuring and Monitoring Port Security 
Reading Intrusion Alerts and Resetting Alert Flags 
clear intrusion-flags 
Clear intrusion flags on all ports. 
port-security [e] < port-number > clear-intrusion-flag 
Clear the intrusion flag on one or more specific ports. 
In the following example, executing show interfaces brief lists the switch’s port 
status, which indicates an intrusion alert on port A1. 
lIntrusion A ert on port 
Figure 11-15.Example of an Unacknowledged Intrusion Alert in a Port Status Display 
If you wanted to see the details of the intrusion, you would then enter the show 
port-security intrusion-log command. For example: 
imes of
MAC Address of latest 
i
l
l
Dates and T
Intrusions 
Intruder on Port A1 
Earlier ntrusions on 
port A1 that have 
already been c eared 
(that is, the Alert Flag 
has been reset at  east 
twice before the most 
recent intrusion 
Figure 11-16.Example of the Intrusion Log with Multiple Entries for the Same Port 
The above example shows three intrusions for port A1. Since the switch can 
show only one uncleared intrusion per port, the older two intrusions in this 
example have already been cleared by earlier use of the clear intrusion-log or 
the port-security < port-list > clear-intrusion-flag command. (The intrusion log 
holds up to 20 intrusion records, and deletes intrusion records only when the 
log becomes full and new intrusions are subsequently added.) The “prior to” 
text in the record for the third intrusion means that a switch reset occurred 
at the indicated time and that the intrusion occurred prior to the reset. 
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