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Problem Note 45416: An MP CONNECT signon failure might occur intermittently on Windows Server 2003

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On Windows Server 2003 platforms, Multi-Processing (MP) CONNECT sign-ons might fail intermittently because of the way that TCP/IP ephemeral ports are handled. The client error messages do not contain much diagnostic information. They typically show only error messages such as these:

   ERROR: A communication subsystem partner link setup request failure has occurred. 
   ERROR: SAS did not start properly. Please ensure that your sascmd value does not attempt
   to run SAS in the background. 
   ERROR: Remote signon to xxx canceled.

You might be able to find the failed SAS server session's start-up error log, which is likely to contain text such as the following:

   ERROR: A communication subsystem environment initialization request failure 
   ERROR: has occurred.
   ERROR: The connection was refused.

Note: These start-up error logs are commonly found under the user's Windows %USERPROFILE% folders, under a (typically hidden) application data folder tree.

On Windows versions before Vista, the path looks like this:

C:\Documents and Settings\user_name\Application Data\SAS\LOGS

Whereas after Vista, the location is typically this:

C:\Users\user_name\AppData\Roaming\SAS\LOGS

The log filenames themselves are of this form: sas.1424.259335D1.log

While not definitive, these client and server error messages do help identify the problem.

The problem occurs when many SAS sessions are running at the same time, consuming TCP/IP sockets, and a new request for a socket pair has a conflict such that the server cannot bind to the ephemeral port that already is in use.

A workaround for this problem is to set the following environment variable to zero before any SAS session is started on the server:

   TCP_EPH_MAP_ENABLED=0 

Use the following steps to add this environment variable setting to your System Variables list so that it is set across reboots of your server:

  1. Open the System panel in your Windows Control Panel.
  2. Click the Advanced tab.
  3. Click the Environment Variables button.
  4. Click the New button under the System variables box.
  5. In the New System Variable window, enter the following in the Variable name field: TCP_EPH_MAP_ENABLED
  6. In the Variable value field, enter 0.
  7. Click the OK button on each window to save the settings and close the windows.


Operating System and Release Information

Product FamilyProductSystemProduct ReleaseSAS Release
ReportedFixed*ReportedFixed*
SAS SystemSAS/CONNECTMicrosoft Windows Server 2003 Datacenter 64-bit Edition9.21_M19.3_M19.2 TS2M09.3 TS1M2
Microsoft Windows Server 2003 Enterprise 64-bit Edition9.21_M19.3_M19.2 TS2M09.3 TS1M2
Microsoft Windows Server 2003 Datacenter Edition9.21_M19.3_M19.2 TS2M09.3 TS1M2
Microsoft Windows Server 2003 Enterprise Edition9.21_M19.3_M19.2 TS2M09.3 TS1M2
Microsoft Windows Server 2003 Standard Edition9.21_M19.3_M19.2 TS2M09.3 TS1M2
Microsoft Windows Server 2003 for x649.21_M19.3_M19.2 TS2M09.3 TS1M2
* For software releases that are not yet generally available, the Fixed Release is the software release in which the problem is planned to be fixed.