steps:-
1. Login to sqlplus as sysdba
2. enable trace, using
alter system set events ‘1017 trace name errorstack level 10’;
3. Show parameter dump
4. Goto the udump location
5. grep ORA – 01017 *
6. get the timestamp and related information from trace generated
7. When trace is no more needed , set it off using:
alter system set events ‘1017 trace name errorstack off’
8. Goto the listener.log file location
9. Get the connectivity information for the selected time from listener log file.
Hope this help. Regards Rupam