ORA-12537 While Connecting To Database Via Listener

Connection to the database server fails with ORA-12537

Local connections working fine but the connection via listener fails with ORA-12537

[oracle@hostname1]$ sqlplus username/password@prodDB

SQL*Plus: Release 11.1.0.7.0

Copyright (c) 1982, 2008, Oracle. All rights reserved.

ERROR:
ORA-12537: TNS:connection closed

Check the listener status :

$lsnrctl status Listener_Name

The listener log for the failing connection shows following error message -

TNS-12518: TNS:listener could not hand off client connection
  TNS-12546: TNS:permission denied
   TNS-12560: TNS:protocol adapter error
    TNS-00516: Permission denied
      Linux Error: 13: Permission denied

Check the listener.log file for additional details.

The OS level error message in the listener log "Linux Error: 13: Permission denied" indicates that the listener was not able to hand off the connection to oracle processes or not able to spawn a new dedicated user process because of lack of permission at the OS level. 

Permissions on oracle binary ( $ORACLE_HOME/bin/oracle ) would not have set correctly.

 To resolve the error -

-          1. Check and correct the permission on /var/tmp/.oracle directory. Permissions on this directory should be 777 with sticky bit set.

            # chmod 01777 /var/tmp/.oracle 

-          2. Check and correct permissions on $ORACLE_HOME/bin/oracle binary and make sure that it is set to 6751.

              $ chmod 6751 $ORACLE_HOME/bin/oracle

Reference Metalink Note :1050756.6

 See Also

- How to prepare for DBA Interview 

- Interview Questions 

- 11G New Features 

- Datapump Scenarios