I opened a SR with oracle and they explained that it has nothing to do with oracle database rather its something with the OS at client and ETL itself. They mentioned its a known issue (though I didnt find this solution in metalink) and following is the action to be taken at the app server where ETL runs. Increase the free port range as follows: Start Registry Editor (Regedt32.exe). Locate the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters On the Edit menu, click Add Value, and then add the following registry value: Edit -> New-> DWORD Value Value Name: MaxUserPort Data Type: REG_DWORD Value: 65534 Valid Range: 5000-65534 (decimal) Default: 0x1388 (5000 decimal) Description: This parameter controls the maximum port number used when an application requests any available user port from the system. Normally, ephemeral (that is, short-lived) ports are allocated between the values of 1024 and 5000 inclusive. ------------------ The change is made and app server is rebooted after that. Datamart ETL is yet to run, so fingers crossed :) On Sun, Apr 18, 2010 at 9:46 AM, Niall Litchfield < niall.litchfield@xxxxxxxxx> wrote: > The same port cannot be used by multiple listeners. One listener can > service multiple databases or multiple services. You cannot however have > multiple processes listening on the same port. I don't see the os but on > Linux at about that release a second listener could be spawned under high > load leading to the symptoms described - this would show up in the fuser > command that jared listed. > > Niall Litchfield > > On Apr 18, 2010 12:35 AM, "Anupam Pandey" <my.oralce@xxxxxxxxx> wrote: > > But this should not be the problem because I can have multiple databases > running on same host > and using the same port (say 1521 ) for listener . > So the same port can be re-used by multiple database listeners. > > Thanks And Regards, > Anupam Pandey > > On Fri, Apr 16, 2010 at 9:49 PM, Jared Still <jkstill@xxxxxxxxx> wrote: > > > On Thu, Apr 15, 2010 a... > >