ORA-12543: TNS: destination host unreachable

Note: [Oracle problem set] refers to the problems and solutions encountered by bloggers during database operations.

Statement execution: indicates the database operation process. Error: Indicates An error occurred while operating the database. Error cause: indicates the cause of the error. Solution: indicates the solution to the error. Related Knowledge: indicates the knowledge related to this topic. ========================================================== ====================================== Execute the statement:Connect database: connect sys/oracle@192.168.135.243/orcl as sysdba Error:ORA-12543: TNS: destination host unreachable Error cause:

Add the ezconnect parameter value to names. directory_path = (tnsnames, ezconnect) in the sqlnet. ora file. Therefore, if you specify a database instance, you must keep up with the Host IP address. See [easy connect naming ]. Therefore, the correct syntax is: CONNECT  username / password @ host [: port ][/ service_name ] For example, connect sys/oracle@192.168.135.243/orcl as sysdba

Solution:

You need to specify the Host IP address when connecting to the database: connect sys/orcl@192.168.135.243/orcl as sysdba

Related Knowledge:The following knowledge is from the official Oracle documentation.

Naming Method	Description
Local naming	Resolves a net Service name stored intnsnames.oraFile stored on a client Local naming is most appropriate for simple distributed networks with a small number of services that change infrequently. See also: "processing ing 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: "processing ing 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 simple 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 Simple TCP/IP 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: "processing ing External naming methods"

Related listening configuration test tool commands: lnsrctl, tnspinglistener. ora file content:

# 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 File Content

# 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