Minor Oracle/SSH Mystery Solved
Apparently, the Oracle Listener works differently on Windows compared to Unix. All the times I’ve done ssh port forwarding has been with Solaris boxes, and forwarding just 1521 has worked fine. Various users have reported problems with this, and it turns out that the Oracle Listener on Windows works like FTP, where the initial communications happens on 1521, and then is redirected over to some other port. This obviously spoils ssh port forwarding or stunnel, and requires you to set up some sort TNS proxy (presumably available from Oracle).
But, this sort of redirection was done on Windows because the TCP/IP stack on NT pre-SP3 was buggy and couldn’t handle any volume. It’s been fixed since, and the Listener behavior can be changed so that it works like the Unix Listeners by a registry change:
Add ‘USE_SHARED_SOCKET = TRUE’ to HKLM\Software\Oracle\HomeX, where X is the OracleHome
The discussion on this topic was over at the stunnel site. There’s also more information at Greenspun.com. Note that this should only be done on Oracle at least as recent as than 8.1.7.1.2 and on WinNT SP3.