Oracle Database Discussions

In the netca GUI, when going through Local Net Service Name configuration, I'm prompted for a hostname, and netca refuses to proceed without one. But there is no field for HOSTNAME in netca.rsp After filling out netca.rsp as much as I can, the tnsnames.ora it generates looks like:

# tnsnames.ora Network Configuration File: /opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

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


The one created by a manual run of netca looks like:

# tnsnames.ora Network Configuration File: /opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

MY_SERVICE =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = MY_HOSTNAME)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = vcas)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)


How do I get the silent install to work properly? I could bang up a script that will add the necessary lines to tnsnames.ora, but I'd prefer that this be done correctly by the installer.