ORACLE PASSWORD FILE (PFILE)
This file contain sysdba password and will be used if any user with sysdba permission is trying to connect database remotely.
It will be in the form of orapw<SID> and resides in ORACLE_HOME/dbs (on unix) and ORACLE_HOME/database. (on windows)
If we forgot password of sys user or lost password file, it can be recreated using ORAPWD utility as follows.
Entires represents those many users can use this password file
Force=y will allow DBA to overwrite password file
To make password file affective, define REMOTE_LOGIN_PASSWORD=EXCLUSIVE.