Oracle 18c Database Installation issue

Question

• Installed 18c express on local computer

• Run the command

  sqlplus / as sysdba

• below is the result,

SQL*Plus: Release 18.0.0.0.0 - Production on Thu May 21 23:45:49 2020 Version 18.4.0.0.0

Copyright (c) 1982, 2018, Oracle. All rights reserved.

ERROR: ORA-12546: TNS: permission denied

Enter user-name: sys Enter password: ERROR: ORA-12546: TNS: permission denied

Enter user-name: SYSTEM Enter password: ERROR: ORA-12546: TNS: permission denied

SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus

Answer 1

If Oracle XE runs on Windows, please follow steps from https://docs.oracle.com/en/database/oracle/oracle-database/18/xeinw/connecting-oracle-database-xe.html

If Oracle XE runs on Linux, please follow steps from https://docs.oracle.com/en/database/oracle/oracle-database/18/xeinl/connecting-oracle-database-xe.html

Answer 2

What specific operating system version are you using? Make sure that the OS user has full permissions on the ORACLE_HOME directory tree, and that your various networking config files (sqlnet.ora, listener.ora) use the IP address for your system, not localhost.