服务器上安装了oracle11g , 防火墙上已经增加1521 入站规则。但是内网客户端配置好了TNS无法连接。telnet 1521 不通。
需要在服务器上\product\10.2.0\db_1\NETWORK\ADMIN\listener.ora 修改
原来是：
LISTENER =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
)
修改为：
LISTENER = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST =IP地址或机器名称)(PORT = 1521)) )
PLSQL Developer 连接时：ORA-12514: TNS: 监听程序当前无法识别连接描述符中请求的服务
新增一个：SID_DESC ORCL是服务名。注意区分大小写
SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (GLOBAL_DBNAME = ORCL) (ORACLE_HOME =D:\app\Administrator\product\11.2.0\dbhome_1) (SID_NAME = ORCL) ) (SID_DESC = (SID_NAME = CLRExtProc) (ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1) (PROGRAM = extproc) (ENVS = "EXTPROC_DLLS=ONLY:D:\app\Administrator\product\11.2.0\dbhome_1\bin\oraclr11.dll") ) )
ORACLE telnet 1521 不通及ORA-12514: TNS: 监听程序当前无法识别连接描述符中请求的服务的解决
原文：http://www.cnblogs.com/andycai/p/4958896.html