preparing the server

  1. we need to install ORACLE network protocol adopter for TCP/IP
  2. we need to configer a special background process called ‘listener’.

  • In one server we can have one or more listeners depending on the load 9the no.of clients’ communications to the server)

  1. While defining the ‘listener’ we provide
  2. Listener name
  3. List of SID’s [databases]
  4. Protocol [TCP/IP]
  5. Port number [default 1521]
  6. One ‘listener’ can have service handlers for one or more instances.
  7. In case of having multiple listeners, they must go with different port numbers.

  • One instance can be listed in one or more instances. Listener : instance ~ m:m [many to many]
  • Listener can be started regardless the status of the instance.

  1. $lsnrctl start [starts the all the listeners]

    1. $ lsnrctl starl ls1 [for 1 listener]

  2. All the listeners are mentioned in

$ORACLE_HOME/network/admin/listener.ora[an ASCLL file]

  1. Using lsnrctl command, we can






$ lsnrctl

LSNRCTL > help  [for more information]


Preparing the client

  1. Install ORACLE network protocol adaptor for TCP/IP [client side components]
  2. We need to define an ALIAS in


  3. While defining an ALIAS, we provide

    1. Alias name
    2. Target server name [or ip address]
    3. Target SID [case sensitive]
    4. Protocol
    5. Port number [usually 1521]

  1. After defining the ALIAS, we check using

    c:\tnsping <ALIANS_NAME>

[‘tnsping’ is the utility for ORACLE, where as ‘ping’ is the utility of TCP/IP]

  1. The client application can be of 2 types

  1. ORACLE client tools [farms/reports]

[in this case we can use ORACLE ‘s native drivens]

  1. Non ORACLE’s applications like v8 or cristal reports

[in this case we need to use odbc drivers in conjuction with ORACLE’s ALIAS]

Applications ratio 30:70

ORACLE products : non ORACLE products

Configuring ODBC [open database connectivity drivers]


Control panel

Odbc 32 bit administration

Create new DSN [data source name]

Provide DSN name

Select ORACLE’s odbc drivers

Choose the ALIAS name what we defined earlier test the new DSN got created.



DNS  domain name server instead of creating server at each client.





ClerkDb down
Clerk rejectDb_auth_failed
Mgr is not availableNo service handler for junk.





Here Neptune works as client & Pluto acts as server to the Neptune


DEMO                   Server SIDE

Dba15 ~] cd $ ORACLE_ HOME/network/admin

Dba15 odmin]$ cp listener.ora $ HOME

Dba15 ~ ] $ vi .bash_profile



Dba15   ~]$  . . bash_profile

Dba15   ~]$   vi listener.ora






Dba15 ~]$  lsnrctl   start listernr_dba15

Dba15 ~]$ p5 –x


lsnrctl> help

[for commands]