How to set affinity of the RouterNT.exe process

  • Article ID: 113093
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  • Updated: 11 Mar 2014

This article describes how to set the affinity of the RouterNT.exe process so that it is bound to one CPU for multi-processor computers.  You may want to do this for the following reasons:

  • The RouterNT.exe process is using higher than expected CPU utilization (greater than 50% for a sustained period of time).
  • The Sophos Remote Management System router logs show any of the following errors:
    • SSLEAY32.dll ????????.???(0) SSLv3_client_method + 12971 caught structured exception ACCESS_VIOLATION (code = c0000005)
    • exception occurred at address 52CFCBBB, attempting to read from memory at address 197623808
    • TAO.dll ????????.???(0) TAO_Incoming_Message_Queue::copy_tail + 57 caught structured exception ACCESS_VIOLATION (code = c0000005)
    • exception occurred at address 526DFE39, attempting to write to memory at address 4
  • There is sustained build-up of message files in the Sophos Remote Management System envelopes folder for multi-processor computers


  • If the version of the Remote Management System (RMS) component is not v3.4 or higher you should upgrade to the latest version of our endpoint security software before continuing.
  • To set the affinity you have to create a registry value on the endpoint computer.  Before attempting the steps below read the warning regarding using the registry editor in article 10388.

Known to apply to the following Sophos products and versions
Sophos Endpoint Security and Control 10.0

What To Do

  1. Open the registry editor (Start | Run | Type: regedit.exe | Press return).
  2. Browse to the following key:
    • 32-bit: HKLM\SOFTWARE\Sophos\Messaging System\Router\
    • 64-bit: HKLM\SOFTWARE\Wow6432Node\Sophos\Messaging System\Router\
  3. Create a new DWORD value called ProcessorAffinity
  4. Set the value to a decimal number between 0 and 31 (inclusive).  The number chosen determines which CPU the process (RouterNT.exe) will be bound to.  For example, to bind the process to CPU 1 set the value of ProcessorAffinity to 1.
  5. Open Windows services (Start | Run | Type: services.msc | Press return).
  6. Restart the Sophos Message Router service.

Technical Information

You can confirm the affinity has been set correctly by checking the top few lines of the newest router log.  In the example below the ProcessorAffinity value is set to 1.

[TIMESTAMP] 0A28 I SOF: C:\ProgramData/Sophos/Remote Management System/3/Router/Logs/Router-DATE-TIME.log
[TIMESTAMP] 0A28 I Sophos Messaging Router starting...
[TIMESTAMP] 0A28 I CPU affinity set to CPU 1

If you need more information or guidance, then please contact technical support.

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