My11gR2 Database on windows 2008 R2 Standard is giving error "ORA-28547: connection to server failed, probable Oracle Net admin error"
This is when i try to login from the server itself
SQL*Plus: Release 188.8.131.52.0 Production on Tue Oct 8 05:43:03 2013
Copyright (c) 1982, 2010, Oracle. All rights reserved.
Enter user-name: sys/**********@orcl as sysdba
"ORA-28547: connection to server failed, probable Oracle Net admin error"
This started happening when the Server was restarted. I am not sure if I have to stop any service, like in some cases on Linux we have to stop iptables service.
The solution I have found on most of the forums is to change in sqlnet.ora from "#SQLNET.AUTHENTICATION_SERVICES = (NTS)" to "#SQLNET.AUTHENTICATION_SERVICES = (NONE)" and restart the listener.
But even this is not working in my case.
#SQLNET.AUTHENTICATION_SERVICES = (NTS)
That "#" makes the line a comment. You could just as well set it to "#sqlnet.authentication_services=fubar"
Also, while you did well in showing us the full and compete output of sqlplus, it would have been even more informative if you had also shown the full and complete command line you used to invoke it.
Also, since you specified "@orcl", you were specifying a network connection even though you were on the same server as the database. What happens if you do the same thing but do not specify " as sysdba"? What happens if you specify a non-privileged user and omit the "as sysdba"? What happens if you invoke sqlplus like this?
sqlplus / as sysdba
When was last time SQL*Net worked without error?
What changed since then?
[oracle@localhost ~]$ oerr ora 28547
28547, 0000, "connection to server failed, probable Oracle Net admin error"
// *Cause: 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.
// -- Hitting Ctrl+C before connection initialization is
// -- Using DRCP on Windows with SQLNET.AUTHENTICATION_SERVICES
// set to NTS.
// -- Connection timeout due to SQLNET.INBOUND_CONNECT_TIMEOUT
// parameter when all shared servers are busy in
// shared server configuration.
// *Action: 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 SID.
// -- Check 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=).
// -- Set SQLNET.AUTHENTICATION_SERVICES to NONE when using DRCP
// on Windows.