Environment
-
Database version: Oracle Database Free 23c (Oracle26ai installation)
-
Operating System: Linux x86_64
-
Oracle Home: /opt/oracle/product/26ai/dbhomeFree
-
Listener host: amyserver
-
Listener port: 1521
-
Services configured: FREE (CDB), FREEPDB1 (PDB)
-
Tools used: sqlplus, tnsping, lsnrctl
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Linux Oracle 9.6
-
Problem Description
-
Unable to connect to Oracle26ai using username and password.
Errors encountered during connection attempts:
-
ORA-01034: ORACLE not available
-
ORA-27101: shared memory realm does not exist
-
ORA-12537: TNS:connection closed
-
ORA-65040: Operation not allowed in a pluggable database
-
ORA-12545: Connect failed because target host or object does not exist
-
OBS: SYSDBA OK
Configured listener.ora LISTNER_FREE on host :(myhostname) port 1521 (ping OK, tnsping ok)
Configured tnsnames.ora with with aliases FREE and FREEPDB1 .
Runing TNSPING for FREE and FREEPDB1 returno OK
tnsname.ora
FREE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = FREE)
)
)
FREEPDB1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = FREEPDB1)
)
)
LISTENER_FREE =
(ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521))
===========================
listner.ora
# listener.ora Network Configuration File
LISTENER_FREE =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521))
)
)
SID_LIST_LISTENER_FREE =
(SID_LIST =
(SID_DESC =
(SID_NAME = FREE)
(ORACLE_HOME = /opt/oracle/product/26ai/dbhomeFree/)
(GLOBAL_DBNAME = FREE)
)
(SID_DESC =
(SID_NAME = FREEPDB1)
(ORACLE_HOME = /opt/oracle/product/26ai/dbhomeFree/)
(GLOBAL_DBNAME = FREEPDB1)
)
)
=============================
lsnrctl status
LSNRCTL for Linux: Version 23.26.0.0.0 - Production on 29-DEC-2025 18:54:32
Copyright (c) 1991, 2025, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=myserver)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 23.26.0.0.0 - Production
Start Date 29-DEC-2025 18:35:18
Uptime 0 days 0 hr. 19 min. 14 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/oracle/product/26ai/dbhomeFree/network/admin/listener.ora
Listener Log File /opt/oracle/diag/tnslsnr/apex/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=myserver)(PORT=1521)))
Services Summary...
Service "45f0e04a90cd3543e065505400a7c825" has 1 instance(s).
Instance "FREE", status READY, has 1 handler(s) for this service...
Service "FREE" has 1 instance(s).
Instance "FREE", status READY, has 1 handler(s) for this service...
Service "FREEXDB" has 1 instance(s).
Instance "FREE", status READY, has 1 handler(s) for this service...
Service "freepdb1" has 1 instance(s).
Instance "FREE", status READY, has 1 handler(s) for this service...
The command completed successfully
Could you help me understand what I should check or do in order to successfully connect to Oracle
Thanks