TNS-12526: TNS:listener: all appropriate instances are in restricted mode


Sometimes You can get “TNS-12526: TNS:listener: all appropriate instances are in restricted mode ” error.


Details of error are as follows.

TNS-12526: TNS:listener: all appropriate instances are in restricted mode
Cause: Database instances supporting the service requested by the client were in restricted mode.
The Listener does not allow connections to instances in restricted mode. This condition may be temporary,
such as during periods when database administration is performed.
Action: Attempt the connection again. If error persists, then contact the database administrator to change
the mode of the instance, if appropriate.

ORA-12526 (TNS-12526)
TNS:listener: all appropriate instances are in restricted mode

ORA-12528 (TNS-12528)
TNS:listener: all appropriate instances are blocking new connections

ORA-12527 (TNS-12527)
TNS:listener: all instances are in restricted mode or blocking

SQL*Plus: Release Production on Tue Apr 28 15:54:21 2018

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Enter user-name: sys as sysdba
Enter password:
ORA-12526: TNS:listener: all appropriate instances
are in restricted mode





This error is related with database in restricted mode.


To solve this error, you can create a static listener and start it as follows.

Add the following listener descriptions to the listener.ora file under $ORACLE_HOME/network/admin.


Check your Hostname, Port, DB Name and fill them correctly.


(ORACLE_HOME = /u01/app/db_home_18c )

[[email protected] ~]$ lsnrctl start LISTENER

The (UR=A) clause for TNS connect strings was created in response to an enhancement request.  This clause can be inserted into the “(CONNECT_DATA=” section of a TNS connect string and allow a privileged or administrative user to connect via the listener even when the service handler is blocking connections for non-privileged users.


Here’s an example of a connect string configured with (UR=A):

          (ADDRESS = (PROTOCOL = TCP)(HOST = <hostname>)(PORT = 1521)))
          (UR=A) <===Add this parameter
          (SERVICE_NAME = <service.domain>)


Please note that the (UR=A) clause is intended to work with a dynamically registered handler so the use of SERVICE_NAME versus SID is required when using dynamic registration (i.e. handler exists in lsnrctl output but is BLOCKED).  The use of SID in a TNS connect string may allow a connection if using a static handler in the listener.ora file under SID_DESC.


Do you want to learn more details about RMAN, then read the following articles.


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About Mehmet Salih Deveci

I am Founder of SysDBASoft IT and IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience.I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource.I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks.I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients.If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress [email protected].-                                                                                                                                                                                                                                                 -Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  [email protected] a mail atabilirsiniz.

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