Network performance slows on Windows XP with Symantec Endpoint Protection 12.1 Release Update 2 Maintenance Pack 1 installed

Article:TECH205486  |  Created: 2013-04-24  |  Updated: 2013-06-06  |  Article URL
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Article Type
Technical Solution



Computers experience network performance problems when the Network Threat Protection (NTP) firewall component of the Symantec Endpoint Protection (SEP) 12.1 Release Update 2 Maintenance Patch 1 (RU2 MP1) client is installed and enabled. Symptoms include:

  • Copying files from a network location over Windows File Sharing takes significantly more time.
  • Programs that are started from a network share take significantly longer to load.
  • Ping responses take longer to return.


This problem is caused by a performance issue introduced with the SEP 12.1 RU2 MP1 NTP firewall driver, teefer2.sys.


This problem is fixed in Symantec Endpoint Protection 12.1 Release Update 3 (12.1 RU3). For information on how to obtain the latest build of Symantec Endpoint Protection, read ‘Obtaining the latest version of Symantec Endpoint Protection or Symantec Network Access Control

If it is not immediately possible to upgrade, work around this problem by using one of the following:

  • Disable the Network Threat Protection firewall on affected computers.
  • Withdraw the Firewall policy in the Symantec Endpoint Protection Manager (SEPM) for groups containing affected computers.
  • Migrate affected computers to Windows Vista or higher
  • Revert affected computers to the a previous version of the SEP client

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