Connection to Oracle ArcSDE geodatabase

[AmdemichaelKelato]

hi everyone.
I have a difficulty to connect to ArcSDE geodatabase which is stored on oracle11g. My problem is arises when I'm try to connecting the geodatases that are stored on remote servers. The first server is on different LAN that my computer is located.The second server is located on the same LAN which my computer is located.And my computer and the geodatabase servers are in the same domain. I need the steps how to connect these ArcSDE geodatabases from the ArcCatalog. is there any additional steps i must do to enable the my geodatabase to be accessed on LAN?
Note: I used ArcGIS dektop 9.3 and the ArcGIS server enterprise (standard) 9.3.

[VinceAngelo]

There is no special networking requirement for ArcSDE beyond TCP/IP connectivity --
I connect (both 3-tier application server and 2-tier Direct Connect) to remote databases
across the Internet via VPN frequently.  It's hard to guess at what your problem might
be without a clearer description of the error(s) you're encountering.

9.3.1 SP2 is the best build of 9.3 -- I recommend upgrade for stability.

- V

[AmdemichaelKelato]

Thanks Vangelo for your quick help. The error message when I'm try to connnect the geodatabase is:
Failed to connect to the specified server.
Entry for SDE instance not found in service file.
What do possibly the problem be?

[VinceAngelo]

That error message is quite specific.  In order to use a symbolic name (e.g., 'esri_sde')
to reference the port of an application server, it must be added to the services file
(/etc/services on Unix, %SystemRoot%\system32\drivers\etc\services on Windows)
of each client.  Your other option is to reference by the port number directly (e.g., "5151").

- V