ORA-28547: connection to server failed, probable Oracle
Net admin error tips
Oracle Error Tips by Stephanie F.
The Oracle docs note this on the
- ORA-28547: connection to server failed, probable Oracle Net
A failure occurred during initialization of a network connection
from a client process to the Oracle server: The connection was
completed but a disconnect occurred while trying to perform
protocol-specific initialization, usually due to use of different
network protocols by opposite sides of the connection.
This usually is caused
by incorrect Oracle Net administrative setup for database links or
external procedure calls. The most frequent specific causes are:
-- The connection uses
a connect string which refers to a Heterogeneous Services agent
instead of an Oracle server.
-- The connection uses
a connect string which includes an (HS=) specification.
Check Oracle Net administration in the following ways:
-- When using
TNSNAMES.ORA or an Oracle Names server, make sure that the client
connection to the ORACLE server uses the correct service name or
LISTENER.ORA on the connection end point"s host machine to assure
that this service name or SID refers to the correct server.
-- Confirm in
TNSNAMES.ORA or the equivalent service definition that the connect
string does NOT contain (HS=).
Per Internet sources, ORA-28547 can
occur on Oracle Net Services; version 10.1.0 to 10.2 when, "Oracle Native
Authentication Services is failing
Client sqlnet trace, level SUPPORT, shows the underlying error is a TNS-12631"
causing "All connections to the database, including
SYSDBA, fail with an ORA-28547"
To resolve ORA-28547, this document states that
the following steps should be taken:
As a workaround disable Oracle Native
Authentication Services. Change SQLNET.AUTHENTICATION_SERVICES from (NTS)
to (NONE) in the server sqlnet.ora
As a solution change the database service to run as a user who is a member
of the Domain Admin group. Oracle Log On user must be a privileged user to
allow it to correctly authenticate the client user for Native
1. Edit the properties of the database service, select the Log On tab
2. Select "This Account" and add you domain admin account details and
3. Shutdown the database
4. Stop and restart the service