Oracle Database Remote Connection I've been searching online for a solution to my problem without any luck. I'm trying to connect to a remote server (~ 700 km of distance), but since I'm new in this Database administration world I'm afraid of messing this up. So I've been practicing with a VirtualBox machine (Windows 7) on my Ubuntu real Machine for almost a week and nothing seems to work.

This are the steps that I'm following to achieve the connection:

ON SERVER SIDE:


Start database: conn sys as sysdba.
Start LISTENER: lsrnctl start on cmd.
listener.ora: 


listener.ora:

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\xe)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\xe)
      (PROGRAM = extproc)
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = ServerHostName)(PORT = 1521))
    )
  )

DEFAULT_SERVICE_LISTENER = (XE)


tnsnames.ora:

XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ServerHostName)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

ORACLR_CONNECTION_DATA = 
  (DESCRIPTION = 
    (ADDRESS_LIST = 
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1)) 
    ) 
    (CONNECT_DATA = 
      (SID = CLRExtProc) 
      (PRESENTATION = RO) 
    ) 
  ) 


ON CLIENT SIDE:

tnsnames.ora:

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /u01/app/oracle/product/11.2.0/xe)
      (PROGRAM = extproc)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
      (ADDRESS = (PROTOCOL = TCP)(HOST = ServerHostName)(PORT = 1521))
    )
  )

DEFAULT_SERVICE_LISTENER = (XE)



Start oracle client: sudo service start oracle-xe start
Try to connect: conn SYS/pass@HostName (tried with different users and host IP)


Please help!
Your connection string is wrong. With easy connect you need to provide a hostname and servicename/SID. In your case you would provide
sqlplus user/"SomePass"@HOSTNAME:$PORT/servicename

If you want to configure your connection in the tnsnames.ora, you can connect to it using sqlplus user/"SomePass"@TNSALIAS

I actually don't understand the part of your question with your local Oracle XE installation. If you only want to connect to a remote database, you don't need it. All you need is an oracle Client (Instant Client with sqlplus will do fine), or a tool like SQLDeveloper. If you are unfamiliar with Database administration a tool like SQLDeveloper might make life a little bit easier.