The WebUI setting for the FTP service has a "Timeout" value setting. This does not update "TimeoutNoTransfer" in the proftpd.conf file. This means that the FTP connection will be dropped after 300 seconds no matter what setting is chosen in the WebUI.

If you set Timeout 7200 in the GUI, the proftp will contain:

TimeoutIdle 7200
TimeoutLogin 300
TimeoutNoTransfer 300
TimeoutStalled 3600

The "TimeoutNoTransfer" still take presendence and kill the connecton with "No transfer timeout (300 seconds): closing control connection" .

It is possible to add "TimeoutNoTransfer 7200" to the Auxcilary parameters, in which case it is added to the bottom of the config file. The first entry still remains and takes precedense and the connection is still dropped.

We have a legacy backup application that goes through each target directory before uploading changed files. Since there are over a million filles this takes some time and 300 seconds is not enough, which means the system times out and aborts the backup process.

I think that the best solution is that the WebUI setting controls both "TimeoutIdle" and "TimeoutNoTransfer". An alternative solution is to add a second control in the WebUI for the "TimeoutNoTransfer" setting.