10g Network Configuration |SQL*Net
About Oracle Net Services
Oracle Net Services provides a Secured and High-availability network
infrastructure for Oracle environment. (Supports network communication)
between a client application and a remote or local database.
Oracle Net is the transport software for communication between client and
database server as well as communication between distributed database
servers. Net8 (called SQL*Net prior to Oracle8).
Connectivity
Oracle Net Services enables a network session from a client application to an
Oracle database server. Once a network session is established, Oracle Net acts
as the data courier for both the client application and the database server.
It is responsible for establishing and maintaining the connection between the
client application and DB server, and exchanging messages between them.
SQL*NET
SQL*NET (OR NET8) is Oracles Client/Server Product.
SQL*NET enables Clients and Servers to connect to each other.
SQL*NET ( Oracle's n/w Software) allows remote data - access between
programs and the Oracle database , or among multiple Oracle Databases.
SQL*Net provides the software layer between Oracle and the networking
software, communication between an Oracle client machine (for ex, SQL*Plus)
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10g Network Configuration |SQL*Net
and the database server or from one database server to another. Net8 is
located on each machine in the network.
SQL*Net Configuration Files
In most basic form , Oracle uses three files for n/w configuration. They are
listener.ora file On Server - Side Setup.
tnsnames.ora file On a Client - Side Setup.
sqlnet.ora file (Optional) - Either server or client side.
SQLNET.ORA
The sqlnet.ora file is the Net8 profile configuration file.
This file is a text file that contains basic configuration details (encryption ,
default domain , tracing options etc ) and used by SQL *Net.
Profiles are stored and implemented using this file.
It resides on the client machines and the database server.
By default, this file is located in the $ORACLE_HOME/network/admin dir.
The database server can be configured with access control parameters in the
sqlnet.ora file. These parameters specify whether clients are allowed or denied
access based on the protocol. (Protocol Parameters Restrict access to
the database)
Profile Parameters for sqlnet.ora
SEND_BUF_SIZE
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RECV_BUF_SIZE
NAMES.DIRECTORY_PATH
NAMES.DEFAULT_DOMAIN
SQLNET.AUTHENTICATION_SERVICES and etc ..
The sqlnet.ora file is created by running netca command.
LISTENER.ORA
Listener.ora is a SQL*Net configuration file.
Listerner.ora file contains server side network configuration parameters.
It is used to configure DB Listeners (to accept remote connection requests).
By default , this file is located in the $ORACLE_HOME/network/admin dir.
Important point to remember, should compulsorily have a listener.ora file
(if users connecting from a different server).
TNSNAMES.ORA
TNSNAMES.ORA is a SQL*Net Configuration file.
It contains information (about the server where our database is present);
For ex : ( The port no , protocol, database service_name) and etc ..
This file contains net service names mapped to connect descriptors for (local
naming method ) or mapped to listener protocol addresses.
By default, this file is located in the $ORACLE_HOME/network/admin dir.
Important point to remember, If a user wants to connect to a database,
that the user would definitely need a tnsnames.ora file.
POINTS TO NOTE
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If million no of users are connecting to a website for ex www.google.com ;
then the user don’t need to have a tnsnames.ora on their own machine ,
because the website is located on a web server , so the tnsnames.ora file
would already be in the webserver.
If NETCA runs successfully , the sqlnet.ora , tnsnames.ora and listener.ora
files will be created automatically with default settings. If NETCA doesn’t
succeed , it is possible to create the files manually.
SQL*Net Protocols
BEQ Bequeath Protocol
TCP Transmission Control Protocol
IPC Inter Process Communications
TCP/IP Transmission Control Protocol/Internet Protocol
Bequeath Protocol
BEQ is a SQL*Net Protocol.
BEQ Connections doesn’t required a listener.
BEQ only used for local connections (Similar to the IPC protocol) .
BEQ enable Clients to connect to the database. I.e.
(Client and Server reside on the same system).
BEQ works only in Dedicated Server mode and not in Shared Server mode.
Database Local connections - where an (Oracle client application - SQL*Plus)
communicates with an Oracle server running on the same machine.
IPC
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IPC Stands for Inter Process Communication.
IPC is a SQL*Net protocol.
A listener is required to make IPC connections.
IPC only used for local connections (similar to the BEQ protocol).
IPC enable Clients to connect to the database. i.e.
(Client and Server reside on the same system).
IPC works on Dedicated Server/Shared Server mode.
Database Local connections - where an (Oracle client application - SQL*Plus)
communicates with an Oracle server running on the same machine.
TCP and TCP/IP
TCP and TCP/IP protocols are supported by SQL* Net.
TCP Transmission control Protocol and used for (remote administration).
TCP/IP is a combination of network and transport level protocols .
TCP/IP is used for CLIENT/SERVER communication over a network.
TCP vs IPC
When we use IPC Connectivity ?
When we use TCP Connectivity ?
We can connect to a local database without any listener only by using IPC.
IPC connection does require listener! Listener only requires TCP and it is
required when two different hosts are involved.
$ sqlplus scott/tiger@orcl This is using TCP.
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$ sqlplus scott/tiger TPC not required but IPC.
When we use ICP Connectivity ?
“ IPC can only be used when the Client and Server reside on the same host
”.
The (IPC) takes place between two processes within the memory space of the
Operating System , so two processes must reside on the same host.
Another important fact is that IPC is only be used by having the Client connect
through the Oracle Listener.
If the Listener is bypassed, the Client and Server processes will use the
(BEQ) Bequeath protocol. Refer Oracle metalink note: IPC Explained [ID
29232.1]
Overview of LISTENER
The Oracle Listener (process) is part of the Oracle network.
This process is only needed on the database server side
The listener is controlled via the lsnrctl utility
The Listener configuration is done via listener.ora
A listener is required for allowing remote (not local) clients to connect to the
Oracle database via the network.
LSNRCTL :- (Listener Control)
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10g Network Configuration |SQL*Net
lsnrctl is an SQL*Net utility used for controlling database listeners.
lsnrctl controls listener functions such as (starting/stopping listeners), and
reporting status of the listeners.
To invoke "lsnrctl" utility from the command line.
$ lsnrctl
LSNRCTL for Linux : Version 10.2.0.1.0 - Production on 02-MAR-2013 09:42:19
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Welcome to LSNRCTL, type "help" for information.
LSNRCTL> help
The following operations are available
An asterisk (*) denotes a modifier or extended command :
start stop status
services version reload
save_config trace spawn
change_password quit exit
set* show*
POINTS TO NOTE :
When a client requests a connection to the DB, (If it is remote to the server)
Clients first contact a listener process ( typically resides on DB Server ), The
listener primary purpose is receives incoming client connection requests and
sends these requests to the DB Server. After the connection is established, the
client and database server communicate directly.
We can configure multiple listeners, each with unique name , in listener.ora
file. Listener configuration stored in listener.ora file.
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$ cat listener.ora (Files edits are in RED )
SID_LIST_LISTENER=
(SID_LIST=
(SID_DESC=
(GLOBAL_DBNAME= orcl.orgdb.com)
(ORACLE_HOME=/u01/app/oracle/product/10.2.0/db_1)
(SID_NAME=orcl )
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST =MYSERVER)(PORT = 1521))
)
)
DB_NAME and DB_DOMAIN parameters combine to create the global
database name and the value assigned to service_names parameter.
LSNRCTL Commands
Start a listener
Stop a listener
Reload a listener
Checking listner status
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Checking Registered Services
To Start a listener
lsnrctl> start listener_name
To Stop a listener
lsnrctl> stop listener_name
Reload a listener
lsnrctl> reload listener_name
To reload a database listener (stop and restart without disrupting the service).
Check listener status
lsnrctl> status listener_name
Status about the listener, including start date, uptime and trace level.
Check registered services
lsnrctl> services listener_name
To see what database services is registered with a listener:
lsnrctl> version
Displays the version information of the listener.
NETCA
NETCA stands for NETwork Configuration Assistant.
NETCA utility is used to configure SQL*Net.
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Screen shots are taken from an OEL system with Oracle 10gR2.
Select add
The default name is LISTENER. (if we wish to change , it is possible)
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10g Network Configuration |SQL*Net
Select which protocols the Listener will use. TCP is selected by default.
Click Next ..
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10g Network Configuration |SQL*Net
The default port number used by an Oracle Listener is 1521
No Option is selected and click the Next button to continue.
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10g Network Configuration |SQL*Net
Click Next ..
The Listener configuration is complete. Click the Next button to complete the
Listener configuration wizard and to return the welcome page.
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10g Network Configuration |SQL*Net
The Listener configuration is completed successfully and that the Listener was
started. Here the listener name is LISTENER_ORCL .
We can validate that the Listener is running by issuing lsnrctl
status. In oracle Terminology , there are two ways database instance
registering with the listener. They are STATIC/DYNAMIC instance
registration.
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10g Network Configuration |SQL*Net
Starting up and shutting down the oracle listener is a routine task for a
database administrator. Let us check how to start, stop, check status of an
oracle listener using Oracle listener control utility LSNRCTL
Before starting, stopping or restarting a listener, manually need to execute
lsnrctl status command to check the oracle listener status.
If Oracle Listener is not running ; [ Error Message ]
$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 08-MAR-2013 21:02:08
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
Linux Error: 111: Connection refused
Oracle listener is not running , so manually start the listener
$ lsnrctl start listener_orcl
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 08-MAR-2013 21:24:34
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Starting /u01/app/oracle/product/10.2.0/db_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 10.2.0.1.0 - Production
System parameter file is
/u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages written to
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/u01/app/oracle/product/10.2.0/db_1/network/log/listener_orcl.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=linuxserver)
(PORT=1521)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=linuxserver)
(PORT=1521)))
STATUS of the LISTENER
Alias listener_orcl
Version TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date 08-MAR-2013 21:24:34
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File
/u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File
/u01/app/oracle/product/10.2.0/db_1/network/log/listener_orcl.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=linuxserver)(PORT=1521)))
Services Summary...
Service "MYDB.PROD.ORCLPROD.COM" has 1 instance(s).
Instance "orclprod", status UNKNOWN, has 1 handler(s) for this service...
Service "MYDB.TEST.ORCLTEST.COM" has 1 instance(s).
Instance "orcltest", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
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Listener name is not case sensitive. i.e listener_ORCL= listener_orcl ;
Listener is running and I am going to stop the listener
$ lsnrctl stop LISTENER_ORCL
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 09-MAR-2013 11:05:23
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=linuxserver)
(PORT=1521)))
The command completed successfully
Reloading the listener
$ lsnrctl reload LISTener_ORcl
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 09-MAR-2013 12:02:58
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=linuxserver)
(PORT=1521)))
The command completed successfully
Checking Registered Services with Listener
$ lsnrctl services
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 09-MAR-2013 12:28:55
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "MYDB.PROD.ORCLPROD.COM" has 1 instance(s).
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Instance "orclprod", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:3 refused:0
LOCAL SERVER
Service "MYDB.TEST.ORCLTEST.COM" has 1 instance(s).
Instance "orcltest", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:8 refused:0
LOCAL SERVER
The command completed successfully
Listener help Show
$ lsnrctl help show
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 09-MAR-2013 12:44:04
Copyright (c) 1991, 2005, Oracle. All rights reserved.
The following operations are available after show
An asterisk (*) denotes a modifier or extended command:
rawmode displaymode
rules trc_file
trc_directory trc_level
log_file log_directory
log_status current_listener
inbound_connect_timeout startup_waittime
snmp_visible save_config_on_stop
About HOST=localhost/127.0.0.1
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10g Network Configuration |SQL*Net
linux> # cat /etc/hosts 127.0.0.1 xxxx xxxxx localhost
If listner configuration is specified "HOST=localhost" or "HOST=127.0.01".
This is a NONROUTABLE IP address .
In # cat etc/ hosts file LOCALHOST and IP ADDRESS 127.0.0.1 always
mean "This machine on which I am sitting". So, all computers are known as
"localhost" or "127.0.0.1".
FYI - No remote client can ever connect to DB Server
using 127.0.0.1
NOTE : If we specify this address, the listener will only be capable of receiving
requests from the machine on which it is running.
Some Points to Remember
The listener is a server side process only.
It creates the connection. It doesn't sustain the connection.
It's entire purpose is to receive requests for connections to databases and set
up those connections. Once the connection is established, the listener is out of
the picture.
Configure Naming Methods : ( Client )
Lets us configure connectivity for client connections to the database server.
Oracle Net supports four(4) naming methods.
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Local Naming
External Naming
Directory Naming
Easy Connect Naming ( EZCONNECT)
EZCONNECT : EZCONNECT is Oracle's easy connect naming method for TCP/IP
environments. This method enables clients to connect to a database server
without any configuration.
LOCAL NAMING : A net service_name stored in tnsnames.ora on a client.
The local naming method stores connect descriptors, identified by their net
service name, in a configuration file (tnsnames.ora).
Connection Requests
When users initiate a connection request , should provide connect string;
A connect string includes a username and password, and a connect identifier;
One of the most common connect identifiers is a net service name;
Here , connect string that uses the net service name;
An example of a Complete Connection String could be scott/tiger@orcl .
SQLPLUS username/password@net_service_name
CONNECT username/password@net_service_name
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10g Network Configuration |SQL*Net
“@” symbol is used to mark the beginning of the connect identifier so the
connect identifier is “orcl”.
When net service name is used , connection processing first mapping to the
connect descriptor. The mapped information that are accessed with naming
methods.
Understading the TNSNAMES.ORA File
The tnsnames.ora is a network configuration file that contains
net_service_name mapped to connect descriptor for the local
naming method. The tnsnames.ora file is used by clients to identify
server destination.
By default , tnsnames.ora is located in the
$ORACLE_HOME/network/admin directory on UNIX/LINUX operating
systems.
Connect Descriptor:
Connect Descriptor (TNS Connect String).
When a Client needs to connect an Oracle Server, should supply three
pieces of information USERID/PASSWORD@NET_SERVICE_NAME.
The net service name provides all necessary information, in the form of a
connect descriptor. The CONNECT DESCRIPTOR usually having two
parts .
ADDRESS DATA Section
CONNECT_DATA Section
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( DESCRIPTION=
( ADDRESS=(address specific things) )
( CONNECT_DATA= (connect data specific things ) ))
The Address data part contains PROTOCOL/HOST/PORT.
The Connect data part contains SERVER/SERVICE_NAME.
The service_name can be same as ORACLE_SID or Global_dbname (defult).
A Connect Descriptor mapping to simple name : ORCLMYTEST
ORCLDB , orcltest =
(DESCRIPTION=
(ADDRESS_LIST =
(ADDRESS= (PROTOCOL=TCP) (HOST=MYSERVER) (PORT=1521)) ) (CONNECT_DATA=
(SERVICE_NAME= orcl.orcldb.com)
(SERVER=DEDICATED )
))
In this example, the destination service is a DB service named orcl.orgdb.com.
A Complete Connect Descriptor
CONNECT scott/tiger@(DESCRIPTION=(ADDRESS=
(PROTOCOL=tcp) (HOST=MYSERVER) (PORT=1521))
(CONNECT_DATA= (SERVICE_NAME= orcl.orgdb.com)))
Example for tnsnames.ora file File edits are in RED
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10g Network Configuration |SQL*Net
ORCLDB , orcltest = TNS alias name
DESCRIPTION =
(ADDRESS_LIST=
(ADDRESS = (PROTOCOL = TCP) (HOST=MYSERVER)
( PORT = 1521)) must, match port in listener.ora
)
(CONNECT_DATA =
(SERVER=DEDICATED)
(SERVICE_NAME =orcl.orcldb.com)
)
)
POINTS TO NOTE
The net_service_names are ‘ORCLDB , ‘orcltest ’.
The service_name is obviously "orcl.orcldb.com" .
'net_service_name' is just another term , same thing as 'tns_alias_name'.
Oracle provides for the ability to have multiple tnsnames aliases for connection
to the same database instance in a standard TNSNAMES.ORA.
POINTS TO REMEMBER
Oracle Net Services , enables a network session from a client application to
an Oracle Database server. Oracle Net is responsible for establishing and
maintaining the connection between the client application and database,
as well as exchanging messages between them.
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10g Network Configuration |SQL*Net
Oracle Client Software is required on workstations.
A client uses a service name to identify the database.
Service name is an identifier of a database service.
Clients use a connect identifier in the connect string to connect to a service.
The connect identifier (sales) that maps to a connect descriptor.
A connect descriptor mapped to simple name called sales.
A connect descriptor is comprised of PROTOCOL/HOST/PORT and the connect
information for the destination service.
sales=
(DESCRIPTION=
(ADDRESS= (PROTOCOL=tcp)(HOST=sales-server)(PORT=1521))
(CONNECT_DATA= (SERVICE_NAME=sales.us.example.com)))
If we don’t specify service_name for the database , the service name is default
to the database's global_name; DB_NAME parameter and the DB_DOMAIN
name parameter combine to create the global database name and value
assigned to the SERVICE_NAMES in the initialization parameter file.
SQLPLUS system/oracle@MYORCL
system/oracle – is the username/password MYORCL – an alias.
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@ – sign indicates that you want to connect to a remote database.
sqlplus – is the binary executable tool you can use to connect to Oracle.
The tnsnames.ora file that will point to the database server to connect. In
order to allow remote connections to an Oracle database the database must
be registered with an Oracle Listener.
When an instance , it registers itself with a listener using one or more service
names. PMON process registers instance information with a listener.
A listener is required for allowing remote (not local) clients to connect to
the Oracle database via the network. A listener.ora file contains
Name of the listener
Database services
Protocol addresses that the listener is accepting connection requests
Address to make remote connection (hostname, listenerport)
The listener knows which services can handle connection requests because an
Oracle database dynamically registers this information with the listener.
This process of registration is called service registration.
If the client is on the same machine as the db instance, it is possible to
connect without referencing tnsnames and without going through the
listener. Now, we can issue a connect , sqlplus scott/tiger
Tnsnames.ora and Listener.ora
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10g Network Configuration |SQL*Net
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10g Network Configuration |SQL*Net
PING and TNSPING
Using ping command , we can verify client connectivity.
If ping doesn’t work, then client is having network issues, and there is no
problem with the server. When a web browser fails to connect to a web site on
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10g Network Configuration |SQL*Net
the Internet or LAN (local area network) the cause is often the web server,
which may be down or overloaded or network failiure.
TNSPING
tnsping is a utility in the $ORACLE HOME/bin directory.
tnsping does only tries to reach (ping) the listener.
tnsping is used to test (SQL*Net) connect string can connect to a listener.
tnsping tests the connection is okay ( tnsping will only report if the
listener process is up ) and the port is open. It doesn’t guarantee that
the database is up and running. It doesn't try to connect to the database . The connection can be established from a client to a server (or server to server).
To Invoke the TNSPING Utility using net service_name
$ tnsping <net_service_name>
net_service_name must exist in tnsnames.ora file.
If the net service name specified , tnsping utility attempts to contact the
corresponding listener. It doesn’t actually determine whether or not the
database itself is running.
$ tnsping <net_service_name>
$ tnsping ORCLTEST
$ tnsping <net_service_name> <count>
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$ tnsping ORCLTEST 5
The “count” parameter is optional and will show the number of times the
command try to connect to the specified net_service_name. The tnsping
reports the number of milliseconds it took to reach the remote service.
TNSPING Utility Using net _ service _ name
$ tnsping ORCLTESTDB
TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 13-MAR-2013
05:13:23
Copyright (c) 1997, 2005, Oracle. All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST =
linuxserver)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED)
(SERVICE_NAME = orcltest)))
OK (10 msec))
TNSPING Utility Using net _ service _ name with Count
$ tnsping orclproddb 4
TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 13-MAR-2013
Copyright (c) 1997, 2005, Oracle. All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
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10g Network Configuration |SQL*Net
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST =
linuxserver)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED)
(SERVICE_NAME =MYDB.PROD.ORCLPROD.COM)))
OK (10 msec)
OK (10 msec)
OK (10 msec)
OK (20 msec)
Some Additional Information about TNSNAMES.ORA
The tnsnames.ora is a network configuration file for the local naming
method on client side. This file is used by clients used to identify server
destinations. In this file net service name s mapped to connect
descriptor. connect descriptor contains two sets of data ; They
are
ADDRESS_LIST and
CONNECT_DATA
DESCRIPTION -- ADDRESS_LIST ----ADDRESS ------PROTOCOL=TCP
------HOST=LINUXSERVER ------PORT=1521 ----CONNECT_DATA ----
SERVER=DEDICATED ------SERVICE_NAME=orcltest
ADDRESS describes how to connect to the server;
CONNECT_DATA describes how to connect to a specific database instance;
SERVER=DEDICATED tells the client to make a direct connection to the server.
General Syntax of tnsnames.ora
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Basic syntax for a tnsnames.ora file
net_service_name=
(DESCRIPTION=
(ADDRESS=(protocol_address_information))
connect_descriptor
(CONNECT_DATA=
(SERVICE_NAME=service_name)))
In this ex : DESCRIPTION contains the connect descriptor, ADDRESS
contains the protocol address, and CONNECT_DATA contains the
database service
identification information.
Oracle Net Naming Methods
In Oracle 10g , Oracle Net provides four naming methods. They are
Local Naming
Directory Naming
Easy Connect Naming
External Naming
LOCAL NAMING
The local naming method stores connect descriptors, identified by their net
service name, in a configuration file (tnsnames.ora) on the client side.
EASY CONNECT NAMING (Central with an LDAP)
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10g Network Configuration |SQL*Net
The easy connect naming method requires no configuration.
The easy connect naming method eliminates the need for service name lookup
in the tnsnames.ora files for TCP/IP environments.
To Invoke EZCONNECT Method
SQL> CONNECT username/password@host[:port][/service_name]
SQL> CONNECT hr/hr@my-server:1521/mydb
HOST/PORT/SERVICE_NAME are required to connect EZCONNECT method.
DIRECTORY NAMING
The directory naming method stores connect identifiers in a centralized, LDAP-
Compliant dir server. Ths is apt for large org with several databases.
DATABASE Connectivity using Easy Connect Method
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10g Network Configuration |SQL*Net
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10g Network Configuration |SQL*Net
DATABASE Connectivity using net_service_name : ( TCP -
Protocol )
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
10g Network Configuration |SQL*Net
DATABASE Connectivity using net_service_name : ( IPC -
Protocol)
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
10g Network Configuration |SQL*Net
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu