Keeping the intrusion log current by resetting alert flags

When a violation occurs on a port, an alert flag is set for that port and the violation is entered in the Intrusion Log. The switch can detect and handle subsequent intrusions on that port, but will not log another intrusion on the port until you reset the alert flag for either all ports or for the individual port.

On a given port, if the intrusion action is to send an SNMP trap and then disable the port (send-disable), and an intruder is detected on the port, then the switch sends an SNMP trap, sets the port's alert flag, and disables the port. If you re-enable the port without resetting the port's alert flag, then the port operates as follows:
  • The port comes up and will block traffic from unauthorized devices it detects.

  • If the port detects another intruder, it will send another SNMP trap, but will not become disabled again unless you first reset the port's intrusion flag.

This operation enables the port to continue passing traffic for authorized devices while you take the time to locate and eliminate the intruder. Otherwise, the presence of an intruder could cause the switch to repeatedly disable the port.