Thanks. Actually the port 23 is not the correct.
One more question:
Is necessary to install the NDV on the Mainframe to the Natural Studio to access a program from MF?
There are multiple ways of transferring mainframe source code to/from the Windows platform, but Natural Studio is the way to go for maintenance and development, and once you have NDV installed on the mainframe, Natural Studio displays the mainframe libraries in its Library Workspace, so you can work with mainframe objects as though they were local objects: drag-n-drop, delete, edit, check, stow, run, debug, etc.
In other words, install NDV and you can use Natural Studio to maintain applications residing on a mainframe.