LISTENER.ORA is a configuration file used to control the operation of an Oracle listener on the server. You can have more than one listener configured in one LISTENER.ORA file if each has a unique name.
The listerner.ora file contains server side network configuration parameters. It can be found in the “$ORACLE_HOME/network/admin” directory on the server. The LISTENER describes an address list or set of address lists. Addresses consist of a protocol definition and a key value, or else a protocol definition, a hostname, and a port number. The generalized Oracle Database 220.127.116.11 standard fresh install LISTENER entry in the listener.ora file follows:
# LISTENER.ORA Network Configuration File: /u01/app/oracle/product/18.104.22.168/network/admin/listener.ora # Generated by Oracle configuration tools. LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521)) ) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC)) ) ) ) SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = PLSExtProc) (ORACLE_HOME = /u01/app/oracle/product/22.214.171.124) (PROGRAM = extproc) ) (SID_DESC = (GLOBAL_DBNAME = prod.com) (ORACLE_HOME =/u01/app/oracle/product/126.96.36.199) (SID_NAME = prod) ) )
The SID_LIST_LISTENER, the second entry in the standard listener.ora file, contains the SID description. The Oracle Database 12c standard SID_DESC is defined by the SID_NAME, ORACLE_HOME, and PROGRAM parameter definitions. The SID_NAME parameter is defined as PLSExtProc, which is used as the extproc identifier. The ORACLE_HOME parameter defines the Oracle home directory. Finally, the PROGRAM parameter defines the extproc agent as the program.