ORA-12560: TNS:protocol adapter error

ORA-12560: TNS:protocol adapter error
Cause: A generic protocol adapter error occurred.
Action: Check addresses used for proper protocol specification. Before reporting this error, look at the error stack and check for lower level transport errors. For further details, turn on tracing and re-execute the operation. Turn off tracing when the operation is complete.


ORA-12560 is defined as a generic protocol adapter exception and may have various reasons.

C:\>sqlplus scott/tiger

SQL*Plus: Release Production on Wed Feb 20 18:44:04 2013

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

ORA-12560: TNS:protocol adapter error

ORA-12560 is common error on Windows that results from any number of different causes. ORA-12560 is also very common exception when we have two Oracle homes. Mostly ORA-12560 occurs when we have Oracle Client configuration related issues but some times it may be due to Server side and network related issues. To resolve ORA-12560 we need to ensure following points:

- Ensure Database Service is up.
- Ensure listener is up and pointing to desired database service.
- Ensure all oracle variables are configured correctly (ORACLE_BASE, ORACLE_HOME, ORACLE_SID, PATH, TNS_ADMIN).
- On Windows: Ensure Full Access is granted to ORACLE_HOME and its sub-directories.
- Also cross-check the firewall & Network configurations.

Related Posts:
- SQLNET: How does Oracle Client connect with Oracle Server
- ORA-12154: TNS:could not resolve the connect identifier specified
- ORA-12545: Connect failed because target host or object does not exist
- ORA-12514: TNS:listener does not currently know of service requested in connect descriptor


  1. Hi All,

    Please check the database is up and and connecting fine in the Database server.
    Then,check the application server from where the DB is connecting and check the cat /etc/hosts in the application box and check if the scan and the vip entries of the db is in the appliacation box

    i am sure the issue will be resolved as I have resolved many issues with the same error.

  2. Ensure the OracleService is running. I keep running into this error, but when I go into Services, find OracleServiceXE and manually start it, the problem is resolved. I have it set to start automatically, but sometimes it just seems to stop on its own; at least, I can't find anything I am doing to stop it.

  3. Hi,

    Could you please tell me how to connect to database that in installed in another machine in network.
    I'm able to connect to shared folder of the system database installed in, but not able to connect to database. It shows the network adapter could not establish the connection error error.

    Vinoth K

    1. you need to use some oracle client like SQL Developer, SQL Plus, Toad or any other.
      What is the issue u r facing??

    2. I have tried with SQL Developer, when I connect it displays "the network adapter could not establish the connection error" error message

    3. read this for better understanding of issue

  4. lsnrctl status

    LSNRCTL for SVR4: Version - Production on 13-MAY-14 12:58:34

    Copyright (c) Oracle Corporation 1994. All rights reserved.

    Connecting to (ADDRESS=(PROTOCOL=TCP)(HOST=
    TNS-12535: TNS:operation timed out
    TNS-12560: TNS:protocol adapter error
    TNS-00505: Operation timed out
    SVR4 Error: 145: Connection timed out

    i am getting this error please help

    1. it is operation timed out. Try to ping ur db machine and tnsping ur db instance.

  5. I get the ORA-12560 error when executing rman target /


  6. En windows el error tambien puede dar porque de active-directory ha desaparecido el grupo de seguridad ORA_DBA que contiene el administrador del sistema y al equipo en que se encuentra la base de datos