How to configure listener.ora file

After Oracle installation you need to configure listener.ora and tnsnames.ora network files.

1: tnsnames.ora

The “listerner.ora” file located under
“$ORACLE_HOME/network/admin”

[oracle@orahow admin]$ more listener.ora
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host-ip-address)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = extproc))
    )
  )
SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = extproc)
      (ORACLE_HOME = /data/oracle/app/product/11.2.0.4/dbhome_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = db11g)
      (ORACLE_HOME = /data/oracle/app/product/11.2.0.4/dbhome_1)
      (SID_NAME = db11g)
    )
  )
INBOUND_CONNECT_TIMEOUT_LISTENER =0

$ lsnrctl start

$ lsnrctl stop
$ lsnrctl reload 

DB11G =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = DB-Server-ip)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = db11g)
    )
  )
EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = extproc))
    )
    (CONNECT_DATA =
      (SID = extproc)
      (PRESENTATION = RO)
    )
  )