客户端连接Oracle报错：ORA-12537：TNS连接已关闭

查看网络服务名是否能正常解析。

[root@localhost oracle]# tnsping orcl
TNS Ping Utility for Linux: Version 12.1.0.2.0 - Production on 08-MAR-2020 07:12:15
Copyright (c) 1997, 2014, Oracle.  All rights reserved.
Used parameter files:
/u01/app/oracle/product/12.1.0/dbhome_1/network/admin/sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.197)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
TNS-12533: TNS:illegal ADDRESS parameters

解析错误TNS-12533: TNS:illegal ADDRESS parameters，查看tnsnames.ora文件发现格式错误：

直接从listener.ora文档复制IP地址过来，修改如下：

[root@localhost oracle]# cat  /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/tnsnames.ora 
# tnsnames.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

orcl =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1523)) //端口是我自己配置的
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1522))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.197)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

(CONNECT_DATA =
      (SID_NAME = orcl)
    )
  )

网络服务名可正常解析了：

[root@localhost oracle]# tnsping orcl

TNS Ping Utility for Linux: Version 12.1.0.2.0 - Production on 08-MAR-2020 07:22:03

Copyright (c) 1997, 2014, Oracle.  All rights reserved.

Used parameter files:
/u01/app/oracle/product/12.1.0/dbhome_1/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1523)) (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1522)) (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.197)(PORT = 1521)) (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))))
OK (10 msec)