About Network Connections and the Oracle Net Listener

Oracle Database Express Edition (Oracle Database XE) supports connections from client applications both remotely over the network and locally. Remote client applications and the database communicate through Oracle Net, which is a software layer that resides both on the remote computer and on the Oracle Database XE host computer. Oracle Net establishes the connection between the client application and the database, and exchanges messages between them using TCP/IP. Oracle Net is automatically installed when you install Oracle Database XE and Oracle Database Express Edition Client.

Included with Oracle Net in an Oracle Database XE installation is the Oracle Net listener, commonly known as the listener. It is the host process that listens on specific TCP/IP ports for connection requests. When the listener receives a valid connection request from a client application, it routes the connection request to the database. The client application and the database then communicate directly.

Table: Types of Connection Requests Handled by the Listener lists the types of connection requests that the listener handles.

Types of Connection Requests Handled by the Listener

Connection Request Type	Default TCP Port Number	Used For
Database	1521	Database connections using Oracle Net over TCP/IP. Examples include: Remote connection from SQL Command Line. Remote connection from a Java application that connects with JDBC.
HTTP	8080	Database connections using the HTTP protocol. Examples include: Accessing the Database Home Page, locally or remotely. See "Accessing the Database Home Page" for more information. Accessing the Oracle XML DB repository. Oracle XML DB is the Oracle Database XE feature that provides high-performance, native XML storage and retrieval. Through the Oracle XML DB repository, you can access XML data with the HTTP and WebDAV (Web folder) protocols. See Oracle XML DB Developer's Guide for more information.

Connection Request Type

Default TCP Port Number

Used For

Database

1521

Database connections using Oracle Net over TCP/IP. Examples include:

Remote connection from SQL Command Line.
Remote connection from a Java application that connects with JDBC.

HTTP

8080

Database connections using the HTTP protocol. Examples include:

Accessing the Database Home Page, locally or remotely. See "Accessing the Database Home Page" for more information.
Accessing the Oracle XML DB repository. Oracle XML DB is the Oracle Database XE feature that provides high-performance, native XML storage and retrieval. Through the Oracle XML DB repository, you can access XML data with the HTTP and WebDAV (Web folder) protocols. See Oracle XML DB Developer's Guide for more information.

Note:

The listener can also handle FTP c onnection requests for the Oracle XML DB repository. For security reasons, FTP requests are disabled when you install Oracle Database XE. See Oracle XML DB Developer's Guide for more information.

You can disable certain types of connection requests by manually stopping the listener, and reenable them by restarting the listener. (The listener is automatically started when you install Oracle Database XE and when you restart the Oracle Database XE host computer.)

Table: Connections That Require the Listener indicates the types of connections that require the listener to be started.

Connections That Require the Listener

Connection Type	Local Connection	Remote Connection
Database	Not required	Required
HTTP	Required	Required

As the table shows, stopping the listener disables all connection requests except local database connection requests.

Configuring the Listener

You can change the ports that the listener listens on, both for database and HTTP connection requests, either during the Oracle Database XE installation process, or at a later time after installation. See "Changing Listener Port Numbers" for details on changing port numbers after installation.

Note:

The Windows installation process prompts for the port number for HTTP requests only if the default port number, 8080, is already in use. The Linux configuration script always prompts for HTTP port number.

Remote HTTP Connections Initially Disabled

As a security measure, remote HTTP connection requests are initially disabled. This means that remote users cannot use the the Oracle Database XE graphical user interface until you enable remote HTTP connections. See "Enabling Remote HTTP Connection to the Database" for instructions.