Windows, ODBC, Oracle, Redirect Packet

Ok, an odd one... 2 Win2K Pro SP4 systems. Both with same MDAC. Both with ODBC drivers. Both attempting to connect to an Oracle server. Reg keys for oracle and odbc are identical. One client works, one does not.

I have put a sniffer on the connection and watched the login sequence (being done via MS Access). In the working case, there is comm between client and server, with the server sending a port redirect back to the client (to use something other than 1521). A couple packets later, the client starts using the redirected port and all is well.

However, on the non-working one, a similar sequence occurs, but when the server sends the redirect packet, the client ignores it and never changes ports. A 2nd redirect packet is sent (and ignored), and then the connection is closed - obviously w/o a successful login.

In the both cases, the port provided as redirect changes, and cycles through several ranges, but on one client, fails none-the-less. I thought and checked on processes/programs/services that might have tied up these ports so the failing client could not use them, but could not find anything.

Has anyone else experienced something similar? I've found many references that explain how this process works - probably a multithreaded oracle server - but nothing that explains when (or why) a client can refuse to switch ports. Actually I found a refernce that implies that a dedicated server might be possible if the proper connect sequence was sent, but the connect sequence from both clients is the same.

Post or email. Received on Wed Apr 07 2004 - 08:50:17 CDT