The inactivity timeout value is the time in seconds without File Transfer Protocol (FTP) server activities that cause the FTP server to close the session. You can keep your FTP connection from timing out.
Certain remote servers allow the client to change this value. For example, the System i™ platform supports the FTP server TIME subcommand, which can be sent to the FTP server with the FTP client QUOTE subcommand. UNIX® servers often support the SITE IDLE subcommand.
When using local i5/OS® FTP subcommands with either the SYSCMD subcommand or F21, there is no interaction between the client and the FTP server. Therefore, if the running of these local FTP commands exceeds the server inactivity timeout period, the server will close the connection. If you lose your connection, log on to the FTP server again using the OPEN command (OPEN <remote system name>) and the USER command.