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Oracle Troubleshooting

ORA-12571: TNS:packet writer failure


The database halts or the current session is terminated with the error:

ORA-12571: TNS:packet writer failure

The error may be observed by a session currently using the database and will appear in the alert log file.

Possible causes and remedies:

  • With Oracle 8.0.4 onwards, this error may indicate that the database is in the process of being shut down.
  • This error has been observed when there was a loose cable connection to the SCSI disk array (on an Oracle Parallel Server system). Related errors were also subsequently noted in the NT event log.
    • If this is the cause then the remedy is to check all the cable connections. Do this by hand rather then visually, since a cable not being firmly in place could cause the problem.
  • Daniel Haller Strahm has reported that this problem can also be caused by an IP address conflict (Oracle 9.0.1). Windows will normally log an IP conflict in the event log and show a pop up alert - but only if it detects the conflict.
    • Check that no other computer on the network has the same IP address as the machine on which the problem has been reported.
  • Robert Wells has reported seeing this error when reinstalling Oracle on Windows 2000. He says it got 46% through configuring the database before this error arose. The solution was to edit the sqlnet.ora file (locations on different systems will vary, but in this case was at D:/Data/ora920/network/admin/sqlnet.ora) and change the line:



    after saving the updated file, he was able to hit the retry button on the install and the creation of the database succeeded.

This page represents one page of many pages of notes I made whilst working with Oracle 7 through to 10i. I now no longer work with Oracle databases, but hope that these notes will continue to be of benefit to others.

About the author: is a dedicated software developer and webmaster. For his day job he develops websites and desktop applications as well as providing IT services. He moonlights as a technical author and consultant.