I installed Oracle with sqlplus with user oracle (linux - CentOS). If I try to connect to database being oracle everything goes as expected (sqlplus / as sysdba for example), but I need to do the same thing (maybe not as sysdba, but as a user from database) being another linux user. I added this second user to group "dba", but still nothing. If, being secondUser, I enter "sqlplus username/password" I get this:
ERROR ORA-12547 TNS: lost contact
Can someone (please) guide me? Thank you in advance.
Most likely it is due to incorrect privileges at OS level. The Oracle file in the $ORACLE_HOME/bin directory should have following privileges:
-rwsr-s--x
You could check it like:
cd $ORACLE_HOME/bin
ls -lrt oracle
If you see any difference, then do:
chmod 6751 oracle
ls -lrt oracle
For more details, see How to resolve ORA-12547: TNS :lost contact when try to connect to Oracle