Using NOCATALOG, which is the default method of connecting to RMAN, one can connect using operating system authentication or Oracle Net Authentication.
D:oracleOra92bin>rman target / nocatalog
Recovery Manager: Release 9.2.0.6.0 - Production
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
connected to target database: SRIDEVI (DBID=937156271)
using target database controlfile instead of recovery catalog
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
connected to target database: SRIDEVI (DBID=937156271)
connected to recovery catalog database
RMAN> CONFIGURE BACKUP OPTIMIZATION ON;
new RMAN configuration parameters:
CONFIGURE BACKUP OPTIMIZATION ON;
new RMAN configuration parameters are successfully stored
starting full resync of recovery catalog
full resync complete
RMAN>
RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 14 DAYS;
new RMAN configuration parameters:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 14 DAYS;
new RMAN configuration parameters are successfully stored
starting full resync of recovery catalog
full resync complete
RMAN> CONFIGURE RETENTION POLICY CLEAR;
old RMAN configuration parameters:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 14 DAYS;
RMAN configuration parameters are successfully reset to default value
starting full resync of recovery catalog
full resync complete