很多人都知道，Oracle的監聽器一直存在著一個安全隱患，假如不設置安全措施，那么能夠訪問的用戶就可以遠程關閉監聽器。

相關示例：

D:>lsnrctl stop eygle

LSNRCTL for 32-bit Windows: Version 10.2.0.3.0 - Production on 28-11月-2007 10:02:40

Copyright (c) 1991, 2006, Oracle.; All rights reserved.

正在連接到 (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=eygle)))命令執行成功

大家可以發現，此時缺省的監聽器的日志還無法記錄操作地址：

No longer listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.33.11)(PORT=1521)))28-NOV-2007 09:59:20 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=)(USER=Administrator))(COMMAND=stop)(ARGUMENTS=64)(SERVICE=eygle)(VERSION=169870080)) * stop * 0

為了更好的保證監聽器的安全，大家最好為監聽設置密碼：

[oracle@jumper log]$ lsnrctl;;;

LSNRCTL for Linux: Version 9.2.0.4.0 - Production on 28-NOV-2007 10:18:17

Copyright (c) 1991, 2002, Oracle Corporation.; All rights reserved.

Welcome to LSNRCTL, type 'help' for information.

LSNRCTL> set current_listener listenerCurrent Listener is listenerLSNRCTL> change_passwordOld password: New password: Reenter new password: Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521)))Password changed for listenerThe command completed successfullyLSNRCTL> set passwordPassword: The command completed successfullyLSNRCTL> save_configConnecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521)))Saved LISTENER configuration parameters.Listener Parameter File; /opt/oracle/product/9.2.0/network/admin/listener.oraOld Parameter File; /opt/oracle/product/9.2.0/network/admin/listener.bakThe command completed successfully

在我們設置密碼后，遠程操作將會因缺失密碼而出現失敗：

D:>lsnrctl stop eygle

LSNRCTL for 32-bit Windows: Version 10.2.0.3.0 - Production on 28-11月-2007 10:22:57Copyright (c) 1991, 2006, Oracle.; All rights reserved.

正在連接到 (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=eygle)))TNS-01169: 監聽程序尚未識別口令

注意：此時在服務器端或客戶端，都需要我們通過密碼來起停監聽器：

LSNRCTL> set passwordPassword: The command completed successfullyLSNRCTL> stopConnecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521)))The command completed successfullyLSNRCTL> startStarting /opt/oracle/product/9.2.0/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 9.2.0.4.0 - ProductionSystem parameter file is /opt/oracle/product/9.2.0/network/admin/listener.oraLog messages written to /opt/oracle/product/9.2.0/network/log/listener.logTrace information written to /opt/oracle/product/9.2.0/network/trace/listener.trcListening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.33.11)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.33.11)(PORT=1521)))STATUS of the LISTENER------------------------Alias;LISTENERVersion; TNSLSNR for Linux: Version 9.2.0.4.0 - ProductionStart Date;;;;;28-NOV-2007 10:22:23Uptime;0 days 0 hr. 0 min. 0 secTrace Level;;;supportSecurity; ONSNMP;;;OFFListener Parameter File; /opt/oracle/product/9.2.0/network/admin/listener.oraListener Log File;;;;;/opt/oracle/product/9.2.0/network/log/listener.logListener Trace File;;;/opt/oracle/product/9.2.0/network/trace/listener.trcListening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.33.11)(PORT=1521)))Services Summary...Service 'eygle' has 1 instance(s). Instance 'eygle', status UNKNOWN, has 1 handler(s) for this service...Service 'julia' has 1 instance(s). Instance 'eygle', status UNKNOWN, has 1 handler(s) for this service...The command completed successfully

另外，ADMIN_RESTRICTIONS參數也是一個重要的安全選項，大家可以在 listener.ora 文件中設置 ADMIN_RESTRICTIONS_ 為 ON，此后所有在運行時對監聽器的修改都將會被阻止，所有對監聽器的修改都必須通過手工修改listener.ora文件才能順利完成。