Oracle Network Configuration

In its most basic form, Oracle uses three files (listener.ora, tnsnames.ora & sqlnet.ora) for network configuration. This article gives an example of each file as a starting point for simple network configuration.

 

• Assumptions
• Listener.ora
• Tnsnames.ora
• Sqlnet.ora
• Testing

Assumptions

The example files below are relevant for an Oracle installation and instance with the following values.

Parameter	Value
HOST	hostname
ORACLE_HOME	/u01/app/oracle/product/9.2.0
ORACLE_SID	ORCL
DOMAIN	world

Listener.ora

The listerner.ora file contains server side network configuration parameters. It can be found in the “$ORACLE_HOME/network/admin” directory on the server. Here is an example of a listener.ora file from Windows 2000.

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = hostname)(PORT = 1521))
      )
    )
  )

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = ORCL.WORLD)
      (ORACLE_HOME = /u01/app/oracle/product/9.2.0)
      (SID_NAME = ORCL)
    )
  )

After the “listener.ora” file is amended the listener should be restarted or reloaded to allow the new configuation to take effect.

C:> lsnrctl stop
C:> lsnrctl start
C:> lsnrctl reload

Tnsnames.ora

The “tnsnames.ora” file contains client side network configuration parameters. It can be found in the “$ORACLE_HOME/network/admin” or “$ORACLE_HOME/net80/admin” directory on the client. This file will also be present on the server if client style connections are used on the server itself. Here is an example of a “tnsnames.ora” file.

ORCL.WORLD =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = hostname)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = ORCL.WORLD)
    )
  )

Sqlnet.ora

The “sqlnet.ora” file contains client side network configuration parameters. It can be found in the “$ORACLE_HOME/network/admin” or “$ORACLE_HOME/net80/admin” directory on the client. This file will also be present on the server if client style connections are used on the server itself. Here is an example of an “sqlnet.ora” file.

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)
NAMES.DEFAULT_DOMAIN = WORLD

# The following entry is necessary on Windows if OS authentication is required.
SQLNET.AUTHENTICATION_SERVICES= (NTS)

Testing

Once the files are present in the correct location and amended as necessary the configuration can be tested using SQL*Plus by attempting to connect to the database using the appropriate username (SCOTT), password (TIGER) and service (ORCL).

$ sqlplus scott/tiger@orcl