Oracle Database Discussions

Aloha!

I badly need your help regarding ORA-12571: TNS:packet writer failure.

I can access an instance using C:\> set ORACLE_SID=SID and C:\> sqlplus / as sysdba running this on the server machine it self.

but when i try to use:

c:> sqlplus sys\password@SID as sysdba

I get this error:

C:\>sqlplus sys/password@orc18 as sysdba

SQLPlus: Release 11.2.0.1.0 Production on Thu Nov 10 14:04:57 2011

Copyright (c) 1982, 2010, Oracle. All rights reserved.

ERROR:
ORA-12571: TNS:packet writer failure
Enter user-name:

But when i try to run the following:

C:\> set ORACLE_SID=SID
C:\>sqlplus schema_name/password

I can access the instance.

Also I try to check the DB connection on remote users(TNS names), same error ORA-12571: TNS:packet writer failure . So all users cant access any of the instances from the server.

Thanks,

Hades