很多人都知道，oracle的监听器一直存在着一个安全隐患，假如不设置安全措施，那么能够访问的用户就可以远程关闭监听器。
相关示例：
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.
正在连接到 (description=(address=(protocol=tcp)(host=172.16.33.11)(port=1521))
(connect_data=(service_name=eygle)))
命令执行成功
大家可以发现，此时缺省的监听器的日志还无法记录操作地址：
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
为了更好的保证监听器的安全，大家最好为监听设置密码：
[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 listener
current listener is listener
lsnrctl> change_password
old password:
new password:
reenter new password:
connecting to (description=(address=(protocol=tcp)(host=172.16.33.11)(port=1521)))
password changed for listener
the command completed successfully
lsnrctl> set password
password:
the command completed successfully
lsnrctl> save_config
connecting 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.ora
old parameter file /opt/oracle/product/9.2.0/network/admin/listener.bak
the command completed successfully
在我们设置密码后，远程操作将会因缺失密码而出现失败：
d:>lsnrctl stop eygle
lsnrctl for 32-bit windows: version 10.2.0.3.0 - production on 28-11月-2007 10:22:57
copyright (c) 1991, 2006, oracle. all rights reserved.
正在连接到 (description=(address=(protocol=tcp)(host=172.16.33.11)
(port=1521))(connect_data=(service_name=eygle)))
tns-01169: 监听程序尚未识别口令
注意：此时在服务器端或客户端，都需要我们通过密码来起停监听器：
lsnrctl> set password
password:
the command completed successfully
lsnrctl> stop
connecting to (description=(address=(protocol=tcp)(host=172.16.33.11)(port=1521)))
the command completed successfully
lsnrctl> start
starting /opt/oracle/product/9.2.0/bin/tnslsnr: please wait...
tnslsnr for linux: version 9.2.0.4.0 - production
system parameter file is /opt/oracle/product/9.2.0/network/admin/listener.ora
log messages written to /opt/oracle/product/9.2.0/network/log/listener.log
trace information written to /opt/oracle/product/9.2.0/network/trace/listener.trc
listening 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 listener
version tnslsnr for linux: version 9.2.0.4.0 - production
start date 28-nov-2007 10:22:23
uptime 0 days 0 hr. 0 min. 0 sec
trace level support
security on
snmp off
listener parameter file /opt/oracle/product/9.2.0/network/admin/listener.ora
listener log file /opt/oracle/product/9.2.0/network/log/listener.log
listener trace file /opt/oracle/product/9.2.0/network/trace/listener.trc
listening 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参数也是一个重要的安全选项，大家可以在 listener.ora 文件中设置 admin_restrictions_ 为 on，此后所有在运行时对监听器的修改都将会被阻止，所有对监听器的修改都必须通过手工修改listener.ora文件才能顺利完成。
更多信息请查看IT技术专栏
