今天有个朋友出现了这么一个情况，在使用pl/sql连接数据库的时候提示ORA-12537：TNS:连接关闭。
查看过程（为了保密，特模拟过程）：
查看过程：
1）查看客户端tnsname.ora文件信息如下：
RHYS =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.101)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = RHYS)
)
)
没有问题
2）查看服务器监听状态
[oracle@oracle-one ~]$ lsnrctl status
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 01-NOV-2013 11:19:35
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=oracle-one)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 01-NOV-2013 11:08:41
Uptime 0 days 0 hr. 10 min. 54 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File /opt/app/oracle/diag/tnslsnr/oracle-one/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=oracle-one)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "RHYS" has 1 instance(s).
Instance "RHYS", status READY, has 1 handler(s) for this service...
Service "RHYSXDB" has 1 instance(s).
Instance "RHYS", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@oracle-one ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Fri Nov 1 11:19:38 2013
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 TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string RHYS
SQL>
正常
3）在客户端使用tnsping：
C:\Users\Administrator>tnsping rhys
TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 01-11月-
2013 11:10:05
Copyright (c) 1997, 2010, Oracle. All rights reserved.
已使用的参数文件:
E:\softsetup\oracle_client\oracle_base\network\admin\sqlnet.ora
已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.1
68.56.101)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = RHYS)))
TNS-12547: TNS: 丢失连接
C:\Users\Administrator>
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