If you have installed an Oracle server or an Oracle client tool on your local system, the TNS is automatically installed with a simple configuration file, tnsnames.ora, to define Oracle connect identifiers.

For example, if you have Oracle XE server installed, you will have the tnsnames.ora located at oraclexeapporacleproduct10.2.0serverNETWORKADMIN. It should contain a connect identifier called XE defined as:

XE =

(DESCRIPTION =

(ADDRESS =

(PROTOCOL = TCP)(HOST = localhost)

(PORT = 1521)

)

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = XE)

)

)