Configuring Oracle Network Environment¶
Oracle Net Listener Configuration¶
The default listener configuration file is called listener.ora, and it is located in the network/admin subdirectory of the Oracle home directory. For example, if your Oracle home directory is /u01/app/oracle/product/12.2.0/dbhome_1, then the listener.ora file is created by default in the /u01/app/oracle/product/12.2.0/dbhome_1/network/admin directory.
The listener is automatically configured when you create a new Oracle database. It just works without any configuration changes.
This default listener is named LISTENER, supports no service names on startup, and listens on the following TCP/IP protocol address:
The oracle database automatically registers with the listener after startip up. Usually it might take a minute or so for the registration to complete.
PMON performs the service registration.
The database can also be manually specified in the
The client uses a connect descriptor to specify the database to which it wants to connect. This connect descriptor contains a protocol and a database service name.
The following example shows a connect descriptor that enables clients to connect to a database with service name
DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=my-server) PORT=1521)) (CONNECT_DATA= (SERVICE_NAME=mydb.us.example.com))
Users initiate a connection request by providing a connect string. A connect string includes a user name and password, and a connect identifier. The connect identifier name is referred to as a net service name.
A naming method is a resolution method used by a client application to resolve a connect identifier to a connect descriptor when attempting to connect to a database service.
Oracle Net provides support for the following naming methods:
- Easy Naming
- Local Naming
- Directory Naming
The easy connect naming method enables clients to connect to an Oracle database by using only a TCP/IP connect string consisting of a host name and service name.
The connection should be in the form
The place holders used in the connect identifier format represent:
- host — the name or IP address of the Oracle database host computer.
- port (optional) — the TCP port number on which the Oracle Net listener listens for connections.
- service_name — a database service name.
- server — the type of service handler. Acceptable values are
Examples of Easy Naming¶
[email protected]"dbhost.example.com/orcl.example.com" [email protected]"192.0.2.1/orcl.example.com" [email protected]"[2001:0DB8:0:0::200C:417A]/orcl.example.com"
The instance name can be found by using the instance parameter as follows
show parameter instance_name.
Oracle database runs on port 1521. If the port is omitted, the clients will connect to port 1521.
Local naming stores the service names in file called
tsnames.ora. This file is located in the ORACLE_HOME/network/admin directory. When you create a database using Oracle Database Configuration Assistant (DBCA), local naming is configured automatically.
Directory naming resolves a database service, net service name, or net service alias to a connect descriptor stored in an LDAP-compliant directory server
Check Listener Status¶
You can use the
lsnrctl command line tool to check the listner status
Start the listener¶
Stop the Listener¶
Connecting to an Oracle Database from a Client Computer¶
- Run the
oraenvcommand line tool to configure the environment variables
- When prompted, enter the user name followed by an at sign (@) and a connect identifier, where the connect identifier has the following format: