Preview Tool

Cisco Bug: CSCtc39241 - ESW500: switchport port security doesn't decrement intermittently

Last Modified

Jan 27, 2017

Products (1)

  • Cisco LAN Switch Software

Known Affected Releases


Description (partial)


Data is being discarded by the switch for one or more devices connected to a switch port.  This problem is seen more often when a PC is connected to an IP phone that is connected to the ESW switch and the IP phone is using PoE.


When the phone (and connected PC) are rebooted there is a race condition where the switchport port security counter is incremented twice erroneously and this causes the switch port security to begin discarding packets.  The user will see the port security logs in the switch logs if this problem is occurring.
Bug details contain sensitive information and therefore require a account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.