Re: TNS-12541 error from tnsping

From: Hans Forbrich <forbrich_at_yahoo.net>
Date: Sun, 25 Jul 2004 05:04:31 GMT
Message-ID: <zbHMc.88054$Rf.64248_at_edtnps84>

Jane Partridge wrote:

> I am trying to connect to a 10g database running on Windows from a few
> client tools but they can't connect. I tried pinging the server using
> tnsping and it returns the following error:
>
> TNS-12541: TNS:no listener
>
> What does this mean and how do I fix it? I am new to Oracle.
>
> Thanks,
>
> Jane

A successful Oracle database connection consists of 3 parts:

1. A client that wants to communicate with a database via Oracle Networking (aka SQL NEt, Net8). In is simpler forms, Oracle Networking is a layer on top of TCP/IP and below things like ADO, ODBC, etc.
2. A Listener on the server that will listen for any client requests coming over the network. Even if you are local to the database, you can think of it this way.

That Listener is usually called a TNS Listener, and is generally listed in the Control Panel, Services screen.

One listener can support several databases on the machine.

3) A database _service_ that consists of one or more processes with one or more threads (thread/process stuff being operating system dependant).

The database service is passed and 'takes over' the client connection from the listener.

..................

Your problem is that you do not have the Listener on, or configured correctly.

Oracle has a tutorial, called an Oracle By Example (OBE) session, at http://otn.oracle.com/obe that runs through a complete and proper installation, generally complete with screen shots.

Unfortunately the last time I looked, the 10g installation OBE was only on Linux. Being a smart and adventurous person, you can probably look at both the 10g/Linux version and the 9i/Windows version and merge the two.

Also, be prepared to spend some significant time on the Oracle

documentation.  That's available on line at http://docs.oracle.com (and
http://tahiti.oracle.com).  Start with the Concepts manual ... also look at
http://oracle.oreilly.com for reference books such as the useful 'Oracle

Essentials'. Check out the http://orafaq.com as well.

G'Luck
/Hans Received on Sun Jul 25 2004 - 07:04:31 CEST