You want to look in the InfoCentre for 5.3. Within the Networking -> TCP/IP section you will find setting up secure FTP (a PDF is available for downloading/printing). Cheers.
Note that sftp is <b>not</b> “FTP” secure or otherwise. It is an unrelated protocol that just <i>happens</i> to have the letters ‘ftp’ and the words ‘File Transfer Protocol’ as part of its name. It is SSH File Transfer Protocol (sometimes called Secure File Transfer Protocol or SFTP). It is indeed <b>a</b> “file transfer protocol” — it just isn’t a FTP protocol. (Nor is it SFTP, which is ‘Simple File Transfer Protocol’ and which doesn’t help clear things up at all.)
FTP on UNIX uses the exact same ports as FTP on i5. Port 22 is not a FTP port on UNIX nor on i5. Port 22 is used by sftp — on both UNIX and i5.
Secure FTP (where the “FTP” is really FTP) is FTP/S. Now is it clear? Whew…
The very unfortunate use of the same words and abbreviations causes unending confusion.
See <a href=”http://www-01.ibm.com/support/docview.wss?uid=nas1fa8ba0d9e5c4cacb8625738c0049ae62″>Ordering 5733SC1- IBM Portable Utilities for i5/OS</a> – for a start on some recent (2009) details about obtaining it. Until you obtain it, there’s not much to say about installing it.