ORA-12514:TNS:监听程序当前无法识别连接描述符中请求的服务

我的rocale10g在脱网状态安装，正脱网状态启动监听后连接数据库没有问题，但当连网状态启动监听报"ORA-12514:TNS:监听程序当前无法识别连接描述符中请求的服务"错误。解决办法修改listener.ora文件。如下:红色字体为增加的部分，host改为主机名。


# listener.ora Network Configuration File: d:\oracle\product\10.2.0\db_1\network\admin\listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = d:\oracle\product\10.2.0\db_1)
      (PROGRAM = extproc)
    )
     (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = D:\oracle\product\10.2.0\db_1)
      (SID_NAME = orcl)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = yangyongming)(PORT = 1521))
    )
  )