There are some details missing, like what you passed as the login username (/) and your sqlnet.ora settings on server and client. When I've debugged cases like this in the past, I find full sqlnet tracing on the server side (trace_level_server=16) to be very helpful. Dan ----- Original Message ---- From: Jack van Zanen <jack@xxxxxxxxxxxx> To: Muhammad.Khan@xxxxxx Cc: oracle-l@xxxxxxxxxxxxx Sent: Wednesday, January 30, 2008 8:53:59 PM Subject: Re: Authentication Problem Look Ok to me, but.... When creating the domain user in the database you use double quotes ( "OPS$<domainname>\<username>" ). It than becomes case sensitive as well. Make sure the case is spot on. log on to the database as a dba user and look in v$session to see exact spelling of your os account. Jack On 31/01/2008, Khan, Muhammad S <Muhammad.Khan@xxxxxx> wrote: Hi Gurus. Its hard to believe what I'm stuck at here right now! I'm testing the OS authentication in my test environment with Oracle 9i database on Unix while client running on Windows. I set the following parameters in the init file for this: os_authent_prefix OPS$ remote_os_authent TRUE remote_login_passwordfile NONE I created the user "OPS$<domainname>\<username>" and granted the necessary privileges required. This username is the same as my windows client user. Now when I'm trying to connect from the client through sqlplus, it prompts me for password and doesn't accept null password. I made different changes in the values for os_authent_prefix and set to "" or remote_os_authent to false but no good. What am I missing here? Is there any catch? Please help as I need to present the output very soon. Thanks, Khan. -- J.A. van Zanen