Oracle Network Products Getting Started Release 2.3.4 for Windows Platforms

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Configuration

• Configuration Overview
• Configuring a Network Without Oracle Names
• Configuring a Network With Oracle Names
• Testing the Configuration on the Server
• Testing the Configuration on the Client
• Closing a Database Connection

Configuration Overview

The LISTENER.ORA file identifies and controls the behavior of the listeners that listen for the databases on the machine. This file includes service names and addresses of all listeners on a machine, the SIDs of the databases they listen for, and various control parameters used by the Listener Control Utility.

Client configuration is accomplished by creating a list of the service names and addresses of network destinations through a TNSNAMES.ORA client configuration file or an Oracle Names Server. A client (or a server that is part of a distributed database) needs this information to tell it where it can make connections.

Configuration is based upon one of two models:

Network Configuration Model...	Suitable For...	Configuration Tool...
Local Naming (no Oracle Names Server)	Networks where network addresses are mapped in a TNSNAMES.ORA configuration file on each node.	SQL*Net Easy Configuration  Oracle Network Manager
Oracle Names Server	Networks where an Oracle Names Server performs network address resolution. An Oracle Names Server stores client configuration profiles in one location.	A centralized, managed network with Oracle Names with the Dynamic Discovery Option (DDO) does not require creating configuration files. If you are using SQL*Net for the first time, and are willing to accept all default parameters, with ANO, the only configuration file needed is a LISTENER.ORA. If you are using Oracle Names without DDO, you must configure using Oracle Network Manager.

  Choosing a configuration tool depends upon whether or not your network uses Oracle Names.

SQL*Net Easy Configuration

• your network administrator has chosen SQL*Net Easy Configuration as your workgroup's network standard
• SQL*Net configuration for your environment is not done by a central administrator (and you know your server name)

Oracle Network Manager

• hierarchical, or "tree view," structure so you can see the relationships among the network services
• map view that shows the network services as they relate to the user's actual network

Simple and Complex Network Considerations

Review the guidelines below before choosing either SQL*Net Easy Configuration or Oracle Network Manager:

• Oracle Corporation only supports configuration files created by using SQL*Net Easy Configuration (for simple database connections) or Oracle Network Manager (for advanced SQL*Net features, such as Oracle Names without DDO and ANO).
• Oracle Corporation strongly recommends that every machine in the workgroup network be configured with one, and only one, of the configuration tools.
• SQL*Net Easy Configuration and Oracle Network Manager are mutually exclusive on any one machine.

Configuring a Network Without Oracle Names

This section describes how to use both products.

Using SQL*Net Easy Configuration

1. From the server or client machine, start SQL*Net Easy Configuration:

On Windows 3.1 or Windows NT 3.51:	Double-click the SQL*Net Easy Configuration icon in the Oracle for Windows/Windows NT program group.
On Windows NT 4.0 or Windows 95:	Choose Start>Programs>Oracle for Windows NT/Windows 95>SQL*Net Easy Configuration.

  The SQL*Net Easy Configuration dialog box appears:



2. Select Add Database Alias and click OK.

The Choose Database Alias dialog box appears:



3. Enter a database alias name to identify the database to access and click OK. The alias can be any name you choose.

The Choose Protocol dialog box appears if more than one Oracle Protocol Adapter resides in your ORACLE_HOME directory. Go to Step 4

.

If you installed only one protocol adapter, the dialog box appropriate for your protocol adapter appears, as shown in Step 4. Go to Step 5.

4. Select the protocol to use for your database alias name and click OK.

The dialog box appropriate for your protocol adapter appears; in the example here, TCP/IP is assumed:



5. Enter the appropriate information for your chosen protocol adapter in the first field and enter the name for the SID of the database to which you want to connect in the Database Instance field. The database instance is typically ORCL.
6. Click OK.

The Confirm Adding Database Alias dialog box appears:



7. Click Yes to confirm.

The SQL*Net Easy Configuration dialog box re-appears.

The configuration files are created in the ORACLE_HOME\NETWORK\ADMIN directory.

Note: You can add up to 15 new database aliases with SQL*Net Easy Configuration.

  The table below describes the results of installing SQL*Net Server and Client and adding a database alias with SQL*Net Easy Configuration:

Action	Result
Install SQL*Net Server and SQL*Net Client	SQLNET.ORA and LISTENER.ORA files are created on the server, and SQLNET.ORA is created on the client.
Run SQL*Net Easy Configuration on the client	SQLNET.ORA is regenerated and TNSNAMES.ORA is created on the client.  If a previous TNSNAMES.ORA file was created, it is moved to TNSNAMES.001.
Run SQL*Net Easy Configuration again on the client	SQL*Net Easy Configuration creates a new TNSNAMES.ORA file, and the older TNSNAMES.ORA is moved to TNSNAMES.OLD.

 

8. Select Exit SQL*Net Easy Configuration and click OK.
9. Go to "Testing the Configuration on the Server" in this chapter.

Using Other SQL*Net Easy Configuration Features

• Modify a Database Alias
• Delete a Database Alias
• View Configuration Information

 

Note:  If you modify or delete a database alias on a server, you have to make the same edits on each of the client machines to ensure the configuration files are consistent.

   

Modify a Database Alias

1. From the server or client machine, start SQL*Net Easy Configuration:

On Windows 3.1 or Windows NT 3.51:	Double-click the SQL*Net Easy Configuration icon in the Oracle for Windows/Windows NT program group.
On Windows NT 4.0 or Windows 95:	Choose Start>Programs>Oracle for Windows NT/Windows 95>SQL*Net Easy Configuration

  The SQL*Net Easy Configuration dialog box appears.
2. Select Modify Database Alias, and click OK.

The Modify Database Alias dialog box appears with the list of database aliases (if any).

3. Select the database alias to modify, and click OK.

The Choose Protocol dialog box appears if you installed more than one Oracle protocol adapter. If not, the Enter Modification Information dialog box appears and you must go to Step 5.

4. Select the protocol to use for your database alias name, and click OK.

The Enter Modification Information dialog box appears.

5. Enter the database alias and other appropriate protocol-specific fields, such as:
• TCP/IP Host Name
• SPX/IPX Service Name
• Named Pipes Server Name
• NetBIOS NTB Name
• Bequeath Computer Name
6. Accept the database instance name or enter the SID of the database in the Database Instance field, and click OK.

Note:  If you used SQL*Net version 1 in the past, you can use the same values for Service Name and Database Instance (SID). If you do not know this information, ask the person who administers your network or remote database.

  The Confirm Modifying Database Alias dialog box appears.
7. Click Yes to modify the Database Alias.

The configuration files for your machine are modified with your edits.

The SQL*Net Easy Configuration dialog box re-appears.

8. Select Exit SQL*Net Easy Configuration and click OK to exit from SQL*Net Easy Configuration.

Delete a Database Alias

1. From the server or client machine, start SQL*Net Easy Configuration:

On Windows 3.1 or Windows NT 3.51:	Double-click the SQL*Net Easy Configuration icon in the Oracle for Windows/Windows NT program group.
On Windows NT 4.0 or Windows 95:	Choose Start>Programs>Oracle for Windows NT/Windows 95>SQL*Net Easy Configuration

 
2. Select Delete Database Alias from the SQL*Net Easy Configuration dialog box, and click OK.

The Delete Database Alias dialog box appears with the list of database aliases.

3. Select the Database Alias to delete, and click OK.

The Confirm Deleting Database Alias dialog box appears with the configuration information for that Database Alias.

4. Select Yes to delete that Database Alias.

The database alias is deleted from the configuration files for the machine you are on.

The SQL*Net Easy Configuration dialog box re-appears.

5. Select Exit SQL*Net Easy Configuration and click OK to exit from SQL*Net Easy Configuration.

View Configuration Information

1. From the server or client machine, start SQL*Net Easy Configuration:

On Windows 3.1 or Windows NT 3.51:	Double-click the SQL*Net Easy Configuration icon in the Oracle for Windows (NT) program group.
On Windows NT 4.0 or Windows 95:	Choose Start>Programs>Oracle for Windows NT/95>SQL*Net Easy Configuration

 
2. Select View Configuration Information from the SQL*Net Easy Configuration dialog box, and click OK.

The Choose Database Alias dialog appears with a list of databases.

3. Select the database alias to view, and click OK.

The Configuration Information dialog box appears with the configuration data for that database alias.

4. View the information, and click OK.

The SQL*Net Easy Configuration dialog box re-appears.

5. Select Exit SQL*Net Easy Configuration and click OK to exit from SQL*Net Easy Configuration.

Using Oracle Network Manager

When using Oracle Network Manager, you:

1. Create a network definition.
2. Save the network definition to a file or database.

Note:  If you want to copy the client files to a Windows workstation, either comment out (REM)--or set the value of OFF--the AUTOMATIC_IPC=ON statement in the SQLNET.ORA file. This prevents a client machine from trying to make a connection through IPC first before trying to use the protocol defined in the TNSNAMES.ORA file.

 
3. Generate the network configuration files.
4. Distribute the network configuration files to the server and each of the client machines.

Creating Configuration Files

1. Start Oracle Network Manager from the Oracle for Windows program group or go to ORAWIN\BIN\NETMAN.EXE from File Manager.

The Oracle Network Manager appears with the Open Network Definition dialog box.

2. Click Cancel.
3. Choose New from the File drop-down menu in the Oracle Network Manager menu bar, or choose the New icon from the Command Tool Bar.

You are asked if you want to have a configuration walk-through. If you click Yes, on-screen instructions appear on how to use Oracle Network Manager.

If you click No, go to Step 4.

4. Choose the Community icon or choose Community from the Create menu to bring up a property sheet for a new community. Use this property sheet to provide information about the protocol (or network community) the clients and servers share.

In the General page of the Community property sheet:

a. Enter TCP for name of the community in the Name field.

b. Select the TCP/IP protocol from the Protocol drop-down list.

c. Click OK to close the property sheet.

TCP.world (the new community) is added to the Treeview.
5. Choose the Node icon or choose Node from the Create menu to bring up a property sheet for a new node. Use this property sheet to provide information about the node on which the Oracle server is installed.

In the Node property sheet:

a. Enter the name of your Windows NT server in the Name field. If you are unsure of the name of your computer, go to the Control Panel and choose the Network icon. It displays a Network dialog that displays the name of your computer.

b. Select User Defined for the Windows NT operating system from the Type drop-down list.

c. Choose the Communities tab, then choose the TCP.world community, and click << Add to add it the Selected list.

d. Click OK to close the page and place the node on the Treeview community.

6. Choose the listener icon or choose Listener from the Create menu to bring up a property sheet for a new listener. Use this property sheet to provide information about the listener for the Oracle7 database.

In the Listener property sheet:

a. The default name LISTENER appears; you do not need to change it unless there is more than one listener for the server. If there are multiple listeners for a server, each listener must have a unique name.

b. If only one node has been defined, it appears in the Node field; you do not need to change it.

c. If more than one has been defined, select the down arrow and select the desired node from the drop-down list box that appears.

d. Select the Addresses tab and click Create. A Service Address property sheet appears in which to define the protocol-specific address of the listener, but do not make any changes, unless you want to change the host to the IP address of the Windows NT machine or the port number from the default.

e. Click OK to close the Service Address property sheet. A short form of the new address displays on the Addresses page.

f. Click OK to exit the Listener property sheet.

7. Choose the Database icon or choose Database from the Create menu to bring up a property sheet for an Oracle7 database.

In the Oracle Database property sheet:

a. Enter the name of the database you want to use in the Name field. This is going to be your SQL*Net connect string. In most cases, you use your SID name if you have multiple SIDs on your database, or your computer name for systems that have one database name.

b. Enter the instance name of the database in the SID field. The default database instance name is ORCL.

c. Click OK to exit from the Oracle Database property sheet.

8. Choose Validate from the File menu of the Oracle Network Manager window to verify that the information you entered is consistent and complete.
9. Save the data you entered into a network definition file by selecting Save from the File menu.

The Save Network Definition dialog box displays the option to save the definition to the file system as a default choice.

a. Click OK. The Save As dialog appears, prompting you for a file name.

b. Enter any name (this example uses GEN) and click OK.

10. Choose Generate from the File menu or choose the Generate icon from the Command Tool Bar to create the configuration files for your network.

a. From the Export Network Definition dialog box that appears, choose File System. The Select a directory dialog box appears.

b. Select the ADMIN directory to save the network configuration files to ORACLE_HOME\NETWORK\ADMIN and click OK.

The configuration files are created.
11. Choose Exit from the File menu.

Results of Oracle Network Manager

• TCP_WORL for the clients
• host_name for the server

Distributing Configuration Files

See Chapter 6, "Distributing the Configuration Files," in the Oracle Network Manager Administrator's Guide for complete information on the various distribution methods, including FTP and NETFETCH.

Configuring a Network With Oracle Names

• destination addresses retrieved from Oracle Names
• Names Servers and listeners transparently listen on predefined TCP/IP ports when initiated

• Choosing Whether to Use Oracle Names and the Dynamic Discovery Option
• Configuration Steps
• Using DDO with SQL*Net Version 2.2 Clients

Choosing Whether to Use Oracle Names and the Dynamic Discovery Option

If you choose to use DDO in your network, you do not have to use Oracle Network Manager to create configuration files. If you are using SQL*Net for the first time, and are willing to accept all default parameters with DDO, the only configuration file needed is a LISTENER.ORA file. That file is created as part of the installation process.

DDO in Oracle Names Servers is not for every network. There are several factors to consider before using DDO on your network.

Yes, Use DDO	No, Do Not Use DDO
If you are setting up a new network, using DDO is a good choice. DDO enables all SQL*Net services on the network to self-register with a well-known Names Server.  This feature eliminates the need for any preconfiguration or maintenance for the network administrator.	If you have multiple naming domains in your network, or expect to grow to the point of needing multiple naming domains, using DDO is not a good choice. DDO relies on the existence of a flat naming space. While a flat naming space is convenient for small, local installations, it is not suitable for large, enterprise-scale networks.
If you have a simple existing network that is growing, DDO is a good choice. Administrative changes can be made in a central location, and distributed to all the clients on the network.	If you have a network that stays the same for long periods of time, whether large or small, converting the network to use DDO may not be worth the effort. Static networks, especially small ones, are easy for an administrator to update or maintain manually.
	If you have networks currently using Native Naming Adapters, carefully evaluate the steps involved in converting to an Oracle Names environment.

 

Configuration Steps

1. Ensure the listener is not running.

From the Control Panel window, double-click Services.

The Services window appears.

2. Check the status of the listener OracleTNSListener. If the listener is stopped (the status column is blank), go to the next step. If the status is Started, stop the listener.

To stop the listener:

a. Select OracleTNSListener (the service name if you are using the default listener name LISTENER) or OracleTNSListenerLSNR (where LSNR is the non-default listener name), and click Stop.

OracleTNSListenerLSNR is only created if the following command has been run:

LSNRCTL START listener_name

A message appears confirming that you want to stop the listener.

b. Click Yes.

The listener is stopped. The status column is blank.

3. Click Close to dismiss the Services window.
4. For all clients, ensure your network administrator has named the Oracle Names Servers as well-known names, allowing clients to access the Oracle Names Servers using the well-known name.

For example, for TCP/IP, Oracle Names Servers may be made well-known by adding aliases oranamesrvr(0-4) to the Domain Name Service (DNS) or
in the /ETC/HOSTS file.

The /ETC/HOSTS file may include the following entries:

144.25.219.146 host0  oranamesrvr0

144.25.219.147 host1  oranamesrvr1

144.25.219.148 host1  oranamesrvr2

This implies you can have as few as one well-known Oracle Names Server (whose alias would be oranamesrvr0) and as many as five (with aliases oranamesrvr0 to oranamesrvr4)

The numbers 0 to 4 indicate the order in which the client tries to contact the Oracle Names Servers, if more than one exists in the network.

The well-known host names for TCP connections	The well-known computer Names for Named Pipes connections1	The well-known service name for an SPX connection
oranamesrvr0  oranamesrvr1  oranamesrvr2  oranamesrvr3  oranamesrvr4	ORANAMESRVR0  ORANAMESRVR1  ORANAMESRVR2  ORANAMESRVR3  ORANAMESRVR4	oranamesrvr

 

Well-known Names Server names for Names Pipes must be in all uppercase.

If you are using DDO, go to Step 6. If you are not using DDO, go to Step 5.

5. If you are not using DDO, use Oracle Network Manager to:

a. Create a network definition using Network Manager property sheets.

b. Generate network component configuration files using the GENERATE command in Oracle Network Manager.

c. Distribute the configuration files to the appropriate nodes on the network.

Additional Information:  These procedures are all described in detail in the Oracle Network Manager Administrator's Guide.

   

Go to Step 8.
6. On every client and the server, edit the SQLNET.ORA file with the NAMES.DIRECTORY_PATH parameter so it includes ONAMES:

NAMES.DIRECTORY_PATH = (ONAMES, TNSNAMES)

7. On every client and server, ensure the following line is in the SQLNET.ORA file:

AUTOMATIC_IPC = OFF

8. On the server, comment out all ADDRESSes (including IPC) that you are not using in the LISTENER.ORA file. For example:

  (ADDRESS_LIST =

#        (ADDRESS=

#          (PROTOCOL= IPC)

#          (KEY= oracle.world)

#        )

#        (ADDRESS=

#          (PROTOCOL= IPC)

#          (KEY= ORCL)

#        )

#        (ADDRESS=

#          (COMMUNITY= NMP.world)

#          (PROTOCOL= NMP)

#          (SERVER= hr-PC)

#          (PIPE= ORAPIPE)

#        )

        (ADDRESS=

          (COMMUNITY= TCP.world)

          (PROTOCOL= TCP)

          (Port= 1521)

        )

        (ADDRESS=

          (COMMUNITY= TCP.world)

          (PROTOCOL= TCP)

          (Port= 1526)

        )

  )

9. On the server, add the GLOBAL_DBNAME parameter for each database instance and USE_PLUG_AND_PLAY_listener_name (for DDO) parameters to the LISTENER.ORA file:

SID_LIST_listener_name=

   (SID_LIST =

      (SID_DESC =

         (SID_NAME = SID)

        (GLOBAL_DBNAME = global_dbname.domain)

      )

   )

USE_PLUG_AND_PLAY_listener_name = ON

GLOBAL_DBNAME

This is the name with which the listener registers the database instance with an Oracle Names Server and the name by which the Oracle Names Server identifies a database.  When clients request the connect information for a database from an Oracle Names Server, this is the alias they use.  The domain is defined in the SQLNET.ORA file by the NAMES.DEFAULT_DOMAIN parameter. The default is set to WORLD.

USE_PLUG_AND_PLAY

Instructs the listener to find and register with a well-known Oracle Names Server.  When the listener starts, it looks for hosts with the well-known host names, tries to gather connection information from the Oracle Names Server, and registers its SID(s) with it.

 
10. Create and start the OracleNamesService by using the Names Control Utility, NAMESCTL. On the Oracle Names Server, enter:

C:\>NAMESCTL

NAMESCTL>START

The OracleNamesService is created and configuration is complete.
11. Go to the section, "Testing the Configuration on the Server".

Using DDO with SQL*Net Version 2.2 Clients

SQL*Net version 2.2 clients cannot automatically find well-known Oracle Names Servers, while SQL*Net version 2.3 can. Adding the NAMES.PREFERRED_SERVERS parameter to the SQLNET.ORA file provides directions to the Oracle Names Servers for SQL*Net version 2.2 clients.

The entry in the SQLNET.ORA looks like:

NAMES.PREFERRED_SERVERS=

   (address_list =

     (address =

       (protocol = tcp)

       (host=oranamesrvr0)

       (port = 1575)

     )

   )

Testing the Configuration on the Server

This section covers the following:

• Step 1: Set Up for a Loopback Test
• Step 2: Perform a Loopback Test on the Server

Step 1: Set Up for a Loopback Test

• Step 1a: Start Oracle Names (only necessary if using Oracle Names)
• Step 1b: Start the Listener

Step 1a: Start Oracle Names

Step 1b: Start the Listener

To start the listener:

Using the Command Line Utility LSNRCTL

Using the Windows NT Control Panel

Verify whether the listener is running or not running.  From the command line enter:  C:\>LSNRCTL.  LSNRCTL> STATUS listener_name  where listener_name is the name of the listener defined in the LISTENER.ORA file with the alias LISTENER. It is not necessary to identify the listener if you are using the default listener, named LISTENER.  If the STATUS command indicates the listener is running, go to Step 2. If the listener is not running, go to Step 3.  Even if the listener is running, Oracle Corporation advises you to stop the listener, and start it again. To stop the listener, enter: LSNRCTL>SET PASSWORD password  LSNRCTL>STOP listener_name  SET PASSWORD is only required if the password is set in the LISTENER.ORA file. The password defaults to ORACLE.  Start the listener. Enter: LSNRCTL>START listener_name  OracleTNSListenerLSNR is created if this command is run for the first time for the first time for a non-default listener name.  Exit from the LSNRCTL utility. Enter: LSNRCTL>EXIT

From the Control Panel window, double-click Services.  The Services window appears. Look for OracleTNSListener (the service name if you are using the default listener name LISTENER) or OracleTNSListenerLSNR (where LSNR is the non-default listener name). OracleTNSListenerLSNR is only created if the following command has been run:  LSNRCTL START listener_name  A blank in the Status column indicates that the service is not running. If the service is already running, close the window and go to the section "Step 2: Perform a Loopback Test on the Server".  Select the service and click Start. The service starts.  In the Services window, click Close.

 

Step 2: Perform a Loopback Test on the Server

This section show how to execute:

• Loopback with Server Manager
• Loopback with SQL*Plus

Loopback with Server Manager

1. Start Server Manager. Enter:

C:\>SVRMGR23

The SVRMGR> prompt appears:



2. Connect to the database. Enter:

SVRMGR>CONNECT SYSTEM/MANAGER@service_name

or

SVRMGR>CONNECT SYSTEM/MANAGER@global_dbname

The service_name is the database alias you defined earlier with SQL*Net Easy Configuration or Oracle Network Manager and the global_dbname is the global database name you defined in the LISTENER.ORA file for the Oracle Names Server.

Server Manager returns the following message:

Connected

You probably do not have to use the full service name. There are two parameters in the SQLNET.ORA file that, if set, automatically add domains to any connect string you use. These parameters are NAMES.DEFAULT_DOMAIN and NAME.DEFAULT_ZONE.

For example, if your service name in the TNSNAMES.ORA file reads ORACLE.WORLD and the two .DEFAULT parameters are set to WORLD in the SQLNET.ORA file, the command to do a loopback is:

SVRMGR> CONNECT SYSTEM/MANAGER@oracle

The two parameters in SQLNET.ORA add a .WORLD extension to ORACLE, which matches the ORACLE.WORLD defined in the TNSNAMES.ORA file.
3. Issue SQL commands.
4. When done, enter:

SVRMGR>EXIT

Exiting Server Manager closes the database connection.
5. Go to the section, "Testing the Configuration on the Client".

Loopback with SQL*Plus

1. Start the SQL*Plus application:

On Windows 3.1 or Windows NT 3.51:	Double-click the SQL Plus 3.3 icon in the Oracle for Windows/Windows NT program group.
On Windows NT 4.0 or Windows 95:	Choose Start>Programs>Oracle for Windows NT/Windows 95>SQL*Plus 3.3.

   
• If you are on Windows NT 3.51, double-click the SQL Plus 3.3 icon.
• If you are on Windows NT 4.0 or Windows 95, select the Programs folder from the Start icon in the Taskbar, then select the Oracle folder, and choose SQL Plus 3.3.
The Log On dialog box appears:



2. Enter SYSTEM in the User Name field, MANAGER in the Password field, and the database alias (from the TNSNAMES.ORA file) or the global database name for the Oracle Names Server (from the LISTENER.ORA file) in the Host String field.
3. Click OK.

The Oracle SQL*Plus window appears with a SQL> prompt.

4. Issue SQL commands.
5. When done, enter:

SQL>EXIT

Exiting SQL*Plus closes the database connection.
6. Go to the next section, "Testing the Configuration on the Client".

Testing the Configuration on the Client

• Step 1: Verify TCP/IP Network Connections (if you are using TCP/IP)
• Step 2: Verify Oracle Database Connections Using TNSPING

Step 1: Verify TCP/IP Network Connections

Most TCP/IP transports attempt to use the Domain Name Service (DNS). DNS is a mechanism used to translate the host name specified in the TNSNAMES.ORA file into the host internet address (IP). If a DNS is present on your network and the TCP/IP vendor supports DNS, the host name is successfully translated to the host address. The host IP address can be determined by using the Control Panel's Network utility to access DNS information.

Depending on your vendor, workstation configuration, and network configuration, your TCP/IP software can also use a HOSTS file to map host names to Internet addresses if DNS is not detected or supported.

If DNS and the HOSTS file are unable to resolve the host name during a remote database connection, the following error message appears:

ORA-12545: TNS: name lookup failure

The following sections explain how to determine the server's IP address and verify that DNS and the HOSTS file are working correctly.

Determine the Server's IP Address

The instructions below explain how to determine the IP address from Windows NT 4.0. The instructions are different on Windows NT 3.51. Please see your operating system documentation for specific DNS information.

To determine the server's TCP/IP internet address:

Note: If you are not authorized for access on the server, ask your server administrator for assistance.

   

1. From the Control Panel window, double-click Network.

The Network window appears.

2. Choose the Protocols tab.

The Protocols view appears:



3. From the Protocol view, select the TCP/IP Protocol adapter and click Properties.

The Microsoft TCP/IP Properties dialog box appears with the IP Address view:



4. Obtain the IP address and click Cancel to close the Microsoft TCP/IP Properties dialog box.
5. Click Cancel to close the Network window.
6. Go to the next section, "Use PING."

Use PING

To use PING:

1. From the client, enter:

C:\>PING server_name

where server_name is the host name, alias, or Internet address of the server to which you are trying to connect. If your network is functioning correctly, the following message appears:

Reply from server_name: bytes=nn time=nnms

If there is a problem, this message appears:

Request timed out

Or:

Reply from server_name: Destination host unreachable

The following is a partial list of reasons why a host is inaccessible:
• the server is not accessible through the network
• the remote host is not online
• the domain name server is not functioning
• a domain name server is not accessible through the network
• the server name does not exist in the HOSTS file
If PING returns an error message, ask your network administrator to help you resolve the problem. If the problem is not resolved, and you attempt to make a SQL*Net connection, you may receive one of the following error messages:
• ORA-12203: TNS: unable to connect to destination
• ORA-12535: TNS: Failure to redirect to destination
• ORA-12541: TNS: no listener
2. Go to the next section, "Step 2: Verify Oracle Database Connections Using TNSPING."

Step 2: Verify Oracle Database Connections Using TNSPING

When you connect to a listener using TNSPING, an estimate of the round trip time in milliseconds appears. If TNSPING fails, a network error message appears without the overhead of a database connection.

To use TNSPING:

From the client, enter:

TNSPING service_name count

The output looks like:

TNS Ping Utility for 32-bit Windows: Version 3.0.2.0.0 - Production on 12-DEC-
96 20:20:33

Copyright, 1996(c) Oracle Corporation 1995. All rights reserved.

Attempting to contact 
(ADDRESS=(COMMUNITY=tcp.world)(PROTOCOL=TCP)(Host=host_name)(Port=1521))

OK (60 msec)

Closing a Database Connection

• Step 1: Stop Oracle Names (if using Oracle Names)
• Step 2: Stop the Listener

Step 1: Stop Oracle Names

Step 2: Stop the Listener

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Copyright © 1997 Oracle Corporation.  All Rights Reserved.

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