ora-12560 in oracle 10g client macine

>when I try to connect sys / as sysdba
conn /@your_sid as sysdba

Well actually you can only use

sqlplus / as sysdba

on the server when you are the proper user (oracle) on a proper setup server system.
In that case a local password file is used to login to your database.

On the client machine there is no such password helping file and you always have to use proper
connect sys/sys_password_here@database_sid_here as sysdba;
to get into it.

The oracle error says it cannot find the database you want to connect to. With a proper setup tnsnames.ora file
database_sid_here should be found.

You can test this with "tnsping database_sid_here" on the command prompt.

When oracle asks for a password it doesn't mean everything is fine. Even when oracle is totally lost, it asks for a password. So one should not think, he is one step further.

Reading starting a server - that is not needed. A client doesn't have to run any oracle service to offer access to a database. That is what servers are for. If there is a firewall between your client and server just make sure that TCP port 1521 is open between them.

Tolomir

Here is my tnsnames.ora in client
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\client_3\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

ORACLE =
 (DESCRIPTION =
   (ADDRESS_LIST =     (ADDRESS = (PROTOCOL = TCP)(HOST = oracle)(PORT = 1521))
  )
   (CONNECT_DATA =
 (SERVICE_NAME = oracle)
 )
 )
----------------------------------
after tnsping oracle
output:

C:\Documents and Settings\Owner>tnsping oracle

TNS Ping Utility for 32-bit Windows: Version 10.2.0.1.0 - Production on 12-OCT-2
008 20:31:20

Copyright (c) 1997, 2005, Oracle.  All rights reserved.

Used parameter files:
C:\oracle\product\10.2.0\client_3\network\admin\sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = oracle)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = oracle)))
TNS-12545: Connect failed because target host or object does not exist

C:\Documents and Settings\Owner>
How can I resolve this?

ping the host with Oracle, seems the host is unreachable