14
DCE and Non-DCE Interoperability

This chapter describes how clients outside DCE can connect to Oracle servers in DCE, and how tnsnames.ora, a local naming configuration file, can be used for name lookup when CDS is accessible.

This chapter contains the following topics:

• Connecting Clients Outside DCE to Oracle Servers in DCE
• Sample Parameter Files
• Using tnsnames.ora for Name Lookup When CDS Is Inaccessible

Connecting Clients Outside DCE to Oracle Servers in DCE

Clients without access to DCE and CDS can still connect to Oracle servers in DCE using TCP/IP or some other protocol if a listener is configured to do this. If a listener has been configured in the listener.ora file on the server, non-DCE clients can use normal Oracle9i and Oracle Net Services procedures to connect to an Oracle server in DCE.

Note: In this case, DCE security is not available to clients. Also, service names are resolved to network addresses and located in a tnsnames.ora file on the client, not using the CDS name server.

The following section includes samples of listener.ora and tnsnames.ora files as they would be configured if a client from outside of DCE wanted to connect to Oracle database servers in a DCE environment.

Sample Parameter Files

At least the following two Oracle parameter files are needed for successful client/server communications; create and modify these files using a text editor:

The parameter files are described in the following sections:

• The listener.ora File
• The tnsnames.ora File

The listener.ora File

The listener.ora file resides on the listener node. It defines listener characteristics and the addresses at which the listener listens.

In the following example, each element is displayed on a separate line, to show the file's structure. This is the recommended format, but you do not have to put each element on a separate line. Be sure to include all the appropriate parentheses, and to indent if you must continue an element on the next line.

This example assumes the UNIX operating system and the TCP/IP protocol for one listener, and the DCE protocol for another listener. A single listener can have multiple addresses. For example, instead of having two separate listeners for different database instances on a server node, you could have one listener for both, listening on both TCP/IP and on DCE. However, performance is improved with separate listeners.

LSNR_TCP=
 (ADDRESS_LIST=
     (ADDRESS=
            (PROTOCOL=IPC)
            (KEY=DB1)
     )
     (ADDRESS=
            (PROTOCOL=tcp)
            (HOST=rose)
            (PORT=1521)
     ))
 SID_LIST_LSNR_TCP=
    (SID_DESC=
           (SID_NAME=ORASID)
           (ORACLE_HOME=/usr/jprod/Oracle9i)
    )
LSNR_DCE=
 (ADDRESS=
 (PROTOCOL=DCE)
 (SERVER_PRINCIPAL=oracle)
 (CELL_NAME=cell1)
 (SERVICE=dce_svc))
 SID_LIST_LSNR_DCE=
 (SID_DESC=
  (SID_NAME=ORASID)
  (ORACLE_HOME=/usr/prod/oracle8))
#For all listeners, the following parameters list sample
#default values.
PASSWORDS_LISTENER=
STARTUP_WAIT_TIME_LISTENER=0
CONNECT_TIMEOUT_LISTENER=10
TRACE_LEVEL_LISTENER=OFF
TRACE_DIRECTORY_LISTENER=/usr/prod/Oracle9i/network/trace
TRACE File_LISTENER=listener.trc
LOG_DIRECTORY_LISTENER=/usr/prod/Oracle9i/network/log
LOG_FILE_LISTENER=listener.log

The tnsnames.ora File

This file resides on both the client and the server nodes. It lists the service names and addresses of all services on the network.

The following sample tnsnames.ora file maps the service name ORATCP to the connect descriptor that includes a TCP/IP address and the service name ORADCE to a connect descriptor that includes a DCE address.

ORATCP = (DESCRIPTION=
     (ADDRESS=
       (PROTOCOL=TCP)
       (HOST=rose)
       (PORT=1521)
      )
      (CONNECT_DATA=
        (SID=DB1)
      )
     )
ORADCE=(DESCRIPTION=
    (ADDRESS=
      (PROTOCOL=DCE)
      (SERVER_PRINCIPAL=oracle)
      (CELL_NAME=cell1)
      (SERVICE=dce_svc)
     )
     (CONNECT_DATA=
            (SID=ORASID)
     )
     )

To access the DB1 database, a user can use ORATCP to identify the appropriate connect descriptor.

For example:

sqlplus scott/tiger@oratcp

Using tnsnames.ora for Name Lookup When CDS Is Inaccessible

Typically, names are resolved into network addresses by CDS. Although the main purpose of the tnsnames.ora file (in the context of native naming adapters) is to load Oracle service names and network addresses into CDS, it could be used temporarily as a backup name resolution service if CDS is inaccessible.

SQL*Net Release 2.2 and Earlier

To use the tnsnames.ora file for name lookup and resolution, remove (or comment out) the "native name" parameters from the sqlnet.ora file on the client. To comment out the lines, add a pound sign (#) at the beginning of each line.

For example:

#native_names.use_native=true
#native_names.directory_path=(dce)

SQL*Net Release 2.3 and Oracle Net Services

You can use tnsnames.ora for name lookup and resolution when DCE CDS is unavailable if you have TNSNAMES listed as a value for the NAMES.DIRECTORY_PATH parameter in the sqlnet.ora file on the client.

For example:

names.directory_path=(dce, tnsnames)

This parameter enables you to list more than one names resolution method. The methods are tried in order. In this example, DCE is attempted first. If it is unsuccessful, TNSNAMES is tried next.