[oracle] How to connect to Oracle 11g database remotely

First, make sure the listener on database server (computer A) that receives client connection requests is running. To do so, run lsnrctl status command.

In case, if you get TNS:no listener message (see below image), it means listener service is not running. To start it, run lsnrctl start command.

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Second, for database operations and connectivity from remote clients, the following executables must be added to the Windows Firewall exception list: (see image)

Oracle_home\bin\oracle.exe - Oracle Database executable

Oracle_home\bin\tnslsnr.exe - Oracle Listener

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Finally, install oracle instant client on client machine (computer B) and run:

sqlplus user/password@computerA:port/XE