【Oracle问题集3】ORA-12543: TNS:destination host unreachable
说明：【oracle问题集】是博主平时操作数据库遇到的问题以及解决方案。
执行语句：表示操作数据库过程
出错现象：表示操作数据库过程出现错误现象
出错原因：表示出现错误的原因
解决方法：表示解决错误的方法
相关知识：表示与这个主题相关的知识
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执行语句：
连接数据库：connect sys/oracle@192.168.135.243/orcl as sysdba
出错现象：
ORA-12543: TNS:destination host unreachable
错误原因：
sqlnet.ora文件中的NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)，添加ezconnect参数值，所以如果指定数据库实例，必须要跟上主机ip地址。请参考【Easy Connect Naming】。因此正确的写法是：CONNECT username/password@host[:port][/service_name]
例如connect sys/oracle@192.168.135.243/orcl as sysdba
解决方法：
连接数据库时需要指定主机ip地址：connect sys/orcl@192.168.135.243/orcl as sysdba
相关知识：
以下知识来源于oracle官方文档
Naming Method Description
Local Naming
Resolves a net service name stored in a tnsnames.ora file stored on a client
Local naming is most appropriate for 易做图 distributed networks with a small number of services that change infrequently.
See Also: "Configuring the Local Naming Method"
Directory Naming
Resolves a database service name, net service name, or net service alias stored in a centralized LDAP-compliant directory server
See Also: "Configuring the Directory Naming Method"
Easy Connect Naming
Enables clients to connect to a database server without any configuration. Clients use a connect string for a 易做图 TCP/IP address, consisting of a host name and optional port and service name:
CONNECT username/password@host[:port][/service_name]
This method is recommended for 易做图 TCP/IP environments.
See Also: "Using the Easy Connect Naming Method"
External Naming
Resolves service information stored in an a third-party naming service
See Also: "Configuring External Naming Methods"
相关监听配置测试工具命令：lnsrctl、tnsping
listener.ora文件内容：
# listener.ora Network Configuration File: /home/oracle/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER=
(SID_LIST=
(SID_DESC=
(SID_NAME=orcl)
(ORACLE_HOME=/home/oracle/app/oracle/product/11.2.0/dbhome_1)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
(ADDRESS = (PROTOCOL = TCP)(HOST=192.168.135.243)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /home/oracle/app/oracle
tnsnames.ora文件内容
# tnsnames.ora Network Configuration File: /home/oracle/app/oracle/product/11.2.0/dbhome_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
ORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST =192.168.135.243)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl.192.168.132.243)
)
)
sqlnet.ora
# sqlnet.ora Network Configuration File: /home/oracle/app/oracle/product/11.2.0/dbhome_1/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
ADR_BASE = /home/oracle/app/oracle
