Configuring the Network Environment

1. Configuring the Network Environment

2. Understanding Network Configuration • A client is any application that needs to connect to the Oracle database to send or retrieve data.  • An Oracle client application can reside on any machine provided it has Oracle client software installed. • Oracle Net is a software component that resides on the client and the Oracle database server. It is responsible for establishing and maintaining the connection between the client application and the server, as well as exchanging messages between them, using industry standard protocols.

3. Understanding Network Configuration • For the client application and a database to communicate, the client application must specify location details for the database it wants to connect to and the database must provide some sort of identification, or address.

4. Server Side • On the database server side, the Oracle Net listener, is a process that listens for client connection requests.  • It is configured in a file named listener.ora, with a protocol address that identifies the database.  • Ex: (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=my-server) (PORT=1521)))

5. Client Side • The client uses a connect descriptor to specify the database it wants to connect to. • This connect descriptor contains a protocol address and a database service name.  • When a client configured with the same protocol address broadcasts a request for a connection, the listener on the server machine brokers the request and forwards it to the Oracle database. • Ex: connect descriptor that enables clients to connect to a database service called mydb.us.acme.com (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=my-server) PORT=1521)) (CONNECT_DATA= (SERVICE_NAME=mydb.us.acme.com)))

6. Connection Requests • Users initiate a connection request by providing a connect string. • A connect string includes a username and password, along with a connect identifier. • Ex: shows a connect string that uses net service name mydb as the connect identifier CONNECT scott/tiger@mydb

7. Naming Methods • With long connect identifiers, you can use a mapping method that maps the net service name to the connect descriptor. • The mapping information is stored in one or more repositories of information that are accessed with naming methods.

8. Naming Methods • Oracle Net provides support for the following mapping methods: • Local Naming • stores connect descriptors in a local (on the client) configuration file named tnsnames.ora • Directory Naming • stores connect identifiers in a centralized LDAP-compliant directory server to access a database service • Easy Connect Naming • enables clients to connect to an Oracle database server by using a TCP/IP connect string consisting of a host name and optional port and service name: CONNECT username/password@host[:port][/service_name] Ex: CONNECT scott/tiger@my-server:1521/mydb • External Naming • stores net service names in a supported non-Oracle naming service.

9. Tools for Network Configuration • Oracle enables you to manage your network configuration with the following tools: • Oracle Net Configuration Assistant. • Enterprise Manager. • Oracle Net Manager.

10. Oracle Net Configuration Assistant • The Oracle Universal Installer launches Oracle Net Configuration Assistant after the database is installed.  •  Oracle Net Configuration Assistant enables you to configure the listening protocol address and service information for an Oracle database.

11. Enterprise Manager • Enables you to manage your server-side network configuration with two pages: • The Listener page • Displays the listener status and enables you to shut it down. • The Net Services Administration page • Enables you to do the following: • Configure the following: • Local naming (tnsnames.ora files) on the machine running the database • Directory naming • Listeners • Search and sort local and directory naming entries • Export directory naming entries to tnsnames.ora file • Perform the following administrative tasks for a selected listener: • Show current status • Change status (start/stop listener) • Change logging settings

12. Oracle Net Manager • Oracle Net Manager provides the same features as Oracle Enterprise Manager with the addition of configuring profiles.  • You can access Oracle Net Manager from the command line or for Windows platforms through the Start menu. • For command line (UNIX, Linux, or Windows) run netmgr. • On Windows choose: Start > Programs > Oracle - home-name > Configuration and Migration Tools > Net Manager

13. Viewing Listener Configuration • The listener runs on your database server machine and brokers incoming client requests.  • To view the status of the listener, navigate to the Enterprise Manager home page. Under General, click Listener. The Listener: listener_name page appears. Under General, note the listener status, which is either Up or Down. • You can additionally view the listener status at the command line using lsnrctl status

14. Starting and Shutting Down the Listener • The Oracle listener is set up to start automatically whenever your server machine is restarted.  • You can also restart it at the command line using the following: lsnrctl start • You can use Enterprise Manager to stop the listener: • Navigate to the Listener: listener_name page by clicking Listener on the Home page. To shut down the listener, click Stop. • You can also stop it at the command line using the following: lsnrctl stop