How to track all the users/machines, which connect an Oracle database

We have a database, which serves multiple users at the factory production floor. We like to find out which computer/user connects to the database. As far as I understand the v$session will provide the info on the computers/users, which are currently connected to the database but we need to capture all computers/users, who have been connecting to the database during last few months.

Any idea?

Thanks,
Ashoke

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