Understanding SQL*Net

Overview of the Configuration Files

This section provides a brief description of the configuration files for each component in the network. It includes the types of information required in each file, and shows the relationships between them. Information about the locations of these files is in Chapter 6, ``Distributing the Configuration Files," of the Oracle Network Manager Administrator's Guide and in the Oracle operating system-specific documentation for your platform. Each file is described in more detail in later sections of this chapter.

Client Configuration Files

Clients typically have three configuration files that are created by Oracle Network Manager. These files provide information about the following:

network destinations

network navigation

tracing and logging, and security (encryption and checksumming)

TNSNAMES.ORA	This file contains a list of the service names and addresses of network destinations. A client (or a server that is part of a distributed database) needs this file to tell it where it can make connections.
Note: This file is not necessary if Oracle Names is used.
Note: This file should be generated and modified by Oracle Network Manager. Do not edit it manually.
TNSNAV.ORA	This file is used only in a network that includes one or more Oracle MultiProtocol Interchanges. It lists the communities of which the client (or server) is a member and includes the names and addresses of the Interchanges available in local communities as a first hop toward destinations in other communities.
Note: This file should be generated and modified by the Oracle Network Manager. Do not edit it manually.
SQLNET.ORA	This file contains optional diagnostic parameters, client information about Oracle Names, and may contain other optional parameters such as native naming or security (encryption and checksumming) parameters.
	Note: SQLNET.ORA may contain node-specific parameters. Unless you are using Oracle Names and the Dynamic Discovery Option, you should create it with Network Manager. You may edit the SQLNET.ORA file for an individual client by using the SQLNET.ORA Editor, which is described in the Oracle Network Products Troubleshooting Guide.

In addition, clients and servers on some protocols may require PROTOCOL.ORA, which you must create manually.

PROTOCOL.ORA This file contains protocol- and platform-specific options for protocols that require them, such as Async and APPC/LU6.2.

Server Configuration Files

Servers in a network that includes distributed databases also require the files that are needed by clients, because when servers connect to other database servers through database links they are, in effect, acting like clients.

In addition to the client configuration files described above, each server machine needs a LISTENER.ORA file to identify and control the behavior of the listeners that listen for the databases on the machine.

LISTENER.ORA This file includes service names and addresses of all listeners on a machine, the system identifiers (SIDs) of the databases they listen for, and various control parameters used by the Listener Control Utility.
Note: Unless you are using Oracle Names and the Dynamic Discovery Option, this file should be generated and modified by the Oracle Network Manager. You should not edit it manually.

Note: LISTENER.ORA and TNSNAMES.ORA contain some similar information. The address of the server in TNSNAMES.ORA is the same as the address of the listener for a server in LISTENER.ORA. Similarly, the address in the TNSNAMES.ORA file includes the SID which is required (as SID_NAME) in the LISTENER.ORA file. Figure A - 1 shows the similarities between these files for a single server.

Figure A - 1. Similarities Between TNSNAMES.ORA and LISTENER.ORA

Interchange Configuration Files

Each Interchange in a network requires three configuration files. The files provide information about the following:

network layout

network navigation

control parameters

TNSNET.ORA	This file contains a list of the communities in the network and the relative cost of traversing them, and the names and addresses of all the Interchanges in the network. This file provides an overview of the layout of the network for all the Interchanges.
TNSNAV.ORA	This file describes the communities of each individual Interchange on the network.
INTCHG.ORA	This file provides both required and optional parameters that control the behavior of each Interchange.

Note: These files should be generated and modified through Oracle Network Manager. They should not be edited by hand.

For detailed information about the configuration files for the Interchange, see the Oracle MultiProtocol Interchange Administrator's Guide.

Oracle Names Configuration Files

Unless you are using the Dynamic Discovery Option, each Names Server in the network requires an individual configuration file called NAMES.ORA, as well as parameters in SQLNET.ORA.

For more information about the NAMES.ORA file for the Names Server, see Chapter 6 in the Oracle Names Administrator's Guide.

NAMES.ORA Unless you are using the Dynamic Discovery Option, every node running a Names Server must have a NAMES.ORA file. NAMES.ORA contains control parameters for the Names Server and points the Names Server to the database where the network definition is stored.
Note: This file should be generated and modified by Oracle Network Manager. Do not edit it manually.
SQLNET.ORA This file contains client information about Oracle Names such as the default domain for service names stored in Oracle Names, and lists preferred Oracle Names Servers. It may also contain optional logging and tracing (diagnostic), native naming, and security (encryption, checksumming, and authentication) parameters.

Oracle SNMP Support Configuration File

Each node managed by Oracle SNMP Support requires a configuration file named SNMP.ORA. The parameters in SNMP.ORA:

identify the services on the node that will be monitored by SNMP

assign index numbers to the services that will be monitored

contain contact information (name and phone number) for each service to be monitored

specify a non-default time interval (in seconds) that the subagent polls an SNMP-managed database

For information on how to configure SNMP support so that the listener, Oracle7 Server, MultiProtocol Interchange, and Oracle Names Server can be queried by any SNMP-based network management system, see the Oracle Network Manager Administrator's Guide and the Oracle operating system-specific documentation.

Note: You must generate the SNMP.ORA file with Network Manager.

For detailed information about the Oracle SNMP Support feature and a description of its Management Information Base (MIB) variables, see the Oracle SNMP Support Reference Guide.

LISTENER.ORA	This file includes service names and addresses of all listeners on a machine, the system identifiers (SIDs) of the databases they listen for, and various control parameters used by the Listener Control Utility.
Note:	Unless you are using Oracle Names and the Dynamic Discovery Option, this file should be generated and modified by the Oracle Network Manager. You should not edit it manually.

NAMES.ORA	Unless you are using the Dynamic Discovery Option, every node running a Names Server must have a NAMES.ORA file. NAMES.ORA contains control parameters for the Names Server and points the Names Server to the database where the network definition is stored.
Note: This file should be generated and modified by Oracle Network Manager. Do not edit it manually.
SQLNET.ORA	This file contains client information about Oracle Names such as the default domain for service names stored in Oracle Names, and lists preferred Oracle Names Servers. It may also contain optional logging and tracing (diagnostic), native naming, and security (encryption, checksumming, and authentication) parameters.