What is the communication port between IM connector server and OS400 endpoint machine?
AS400 java connector uses the IBM Java Toolbox (jt400__V5.1.1.jar) to access to AS400 endpoints.
Assuming the port assignments have not been modified (native "WRKSRVTBLE" command),
the IBM JT kit uses the default ports 449 and 8475 for remote commands if no-SSL or 9475 if SSL is set.