监听就是数据库与数据库，客户端与服务端之间的网络沟通桥梁。
以下是配置监听的一些过程。

1、配置监听的设备：

两台机器：

服务端：HOST = 192.168.2.4

客户端：HOST = 192.168.2.6

2、配置监听
1》服务端：

动态：

LISTENER =

  (DESCRIPTION_LIST =

    (DESCRIPTION =

      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.2.4)(PORT = 1521))

      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

    )

  )

静态：

SID_LIST_LISTENER=

  (SID_LIST=

    (SID_DESC=

     (GLOBAL_DBNAME=ORA11GR2)

     (ORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1)

     (SID_NAME=ORA11GR2))

2》客户端：（试验两个链接名）

:连接名1：

11 =

  (DESCRIPTION =

    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.2.4)(PORT = 1521))

    (CONNECT_DATA =

      (SERVER = DEDICATED)

      (SERVICE_NAME = ORA11GR2)

    )

  )

连接名2：

12 =

  (DESCRIPTION =

    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.2.4)(PORT = 1521))

    (CONNECT_DATA =

      (SERVER = DEDICATED)

      (SERVICE_NAME = ORA11GR2)

    )

  )

3、测试配置是否成功：
1》服务端：

打开数据库：查看监听状态：

lsnrctl status

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.2.4)(PORT=1521)))

TNS-12541: TNS:no listener

 TNS-12560: TNS:protocol adapter error

  TNS-00511: No listener

打开监听：

lsnrctl start

STATUS of the LISTENER

------------------------

Alias                     LISTENER

Version                   TNSLSNR for Linux: Version 11.2.0.4.0 - Production

Start Date                10-OCT-2016 14:07:06

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/11.2.0/dbhome_1/network/admin/listener.ora

Listener Log File         /u01/app/oracle/diag/tnslsnr/oracle/listener/alert/log.xml

Listening Endpoints Summary...

  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.2.4)(PORT=1521)))

  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

Services Summary...

Service "ORA11GR2" has 1 instance(s).

  Instance "ORA11GR2", status UNKNOWN, has 1 handler(s) for this service...

The command completed successfully

打开成功。

2》客户端检测连接：

连接名1：

tnsping 11

Used TNSNAMES adapter to resolve the alias

Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.2.4)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ORA11GR2)))

OK (70 msec)

[oracle@enmo admin]$

能ping通。

连接名2：

tnsping 12

Used TNSNAMES adapter to resolve the alias

Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.2.4)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ORA11GR2)))

OK (0 msec)

[oracle@enmo admin]$

能ping通。

4、连接数据库：

连接名1 ：

[oracle@enmo admin]$ sqlplus  sys/skysky@11 as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Oct 10 14:12:08 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> show parameter service_name

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

service_names                        string      ORA11GR2

连接成功。

连接名1 ：

[oracle@enmo admin]$ sqlplus  sys/skysky@12 as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Oct 10 14:13:16 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> show parameter service_name

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

service_names                        string      ORA11GR2

连接成功。

以上的服务端用到了两种监听，一个是动态监听，另一个是静态监听，在连接过程中，有一个或者两个都可以，只要配置正确，
都能实现服务端与客户端之间的链接。当然，还可以改变连接端口，只不过是一般默认情况下的端口为PORT=1521。可以
把改了PORT=1522，PORT=1526等等。