Where the init.ora , tnsnames.ora, listener.ora, sqlnet.ora

Question

If client-side and server-side software are located in different machines, basically, init.ora and listener.ora are located in the server-side, and tnsnames.ora and sqlnet.ora are located in the client-side, am I right?

Answer 1

The confusion comes because, as stated earlier by Sanjay, a server could also be a client...
Here a very simple example on one and only one Windows machine with the same user :
---here it is a connection as from client
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>tnsping demo111p
TNS Ping Utility for 32-bit Windows: Version 11.1.0.7.0 - Production on 21-JUN-2009 09:36:38
Copyright (c) 1997, 2008, Oracle.  All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = phoenix)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = DEMO111P)))
OK (10 msec)
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>sqlplus scott/demo111@demo111p
SQL*Plus: Release 11.1.0.7.0 - Production on Sun Jun 21 09:27:02 2009
Copyright (c) 1982, 2008, Oracle.  All rights reserved.
Connected to:
Personal Oracle Database 11g Release 11.1.0.7.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> quit
Disconnected from Personal Oracle Database 11g Release 11.1.0.7.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
--- we remove the sqlnet.ora
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>rename sqlnet.ora _sqlnet.ora
---here it is a connection as from client
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>tnsping demo111p
TNS Ping Utility for 32-bit Windows: Version 11.1.0.7.0 - Production on 21-JUN-2009 09:37:30
Copyright (c) 1997, 2008, Oracle.  All rights reserved.
Used parameter files:
TNS-03505: Failed to resolve name
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>sqlplus scott/demo111@demo111p
SQL*Plus: Release 11.1.0.7.0 - Production on Sun Jun 21 09:27:11 2009
Copyright (c) 1982, 2008, Oracle.  All rights reserved.
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified
Enter user-name:
---here it is a connection as from server, still working, in that case it does not use tnsnames/sqlnet
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>set ORACLE_SID=demo111p
E:\apps\oracle\ora1110PE\NETWORK\ADMIN>sqlplus scott/demo111
SQL*Plus: Release 11.1.0.7.0 - Production on Sun Jun 21 09:27:37 2009
Copyright (c) 1982, 2008, Oracle.  All rights reserved.
Connected to:
Personal Oracle Database 11g Release 11.1.0.7.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL>So, we are on server, the behaviour change depending what we are connecting with (client or server method).
Nicolas.