Unable to establish the connection with the database ORA-12541: TNS: No Listener.


Article ID: 154322


Updated On:


Data Loss Prevention Enforce


We get the error 'Unable to establish the connection with the database. ORA-12541: TNS: No Listener.' This is common when attempting to run the URT from the Enforce server fails each time attempted. 

Error: unable to establish db connection for user protect: ORA-12541:  TNS:no listener


It could be possible that the Listener service is not running on the Oracle Server.


To resolve the issue, follow the steps below:

  1. Check if the Listener service is running on the Oracle Server. If not, start the Listener service.
  2. If the ORACLE_HOME path or the %ORACLE_HOME%\bin path do not exist on the system you may need to add them.
    • Add the ORACLE_HOME to the system environment variables on the Enforce server. 
    • Add %ORACLE_HOME%\bin to the system PATH variable on the Enforce server. 
  3. If it was already running, then ensure that the supplied destination address matches one of the addresses used by the listener - compare the TNSNAMES.ORA (Enforce) entry with the appropriate LISTENER.ORA (Oracle) file.
    • \<Oracle Home>\product\<Oracle Version>\client_1\NETWORK\ADMIN\tnsnames.ora
    • \<OracleHome>\product\<Oracle Version>\db_1\network\admin\Listener.ora
  4. Open the Listener.ora file and verify if the listener is configured to listen for incoming requests on the same port as the tnsnames.ora.