Problem

FTP client does not issue the QUIT command before disconnection and the transfers often appear as INTERRUPTED in Gateway.

Resolution

* Gateway is both an FTP server and a transfer monitor. The transfers are successful, and the transferred files can be used as they are. The monitor adds value by checking whether transfers are successful and applying additional operations on the transferred files. In this case, the transfer works, but is closed poorly, so the monitor marks it as interrupted. This is a safe interpretation of events, since we cannot guarantee anything more than this.

Gateway can force the FTP client to wait before disconnecting. By adding this delay in the response, preventing simple FTP clients from disconnecting at an ambiguous point in time. When enabling a pre_resp_timer=x, Gateway will wait x seconds before sending a 226 back to the client. In most cases, this will give the client time to close the data channel but force it to keep the control connection alive. The only downside to this workaround is that connections will stay alive x seconds longer than usual. When using the parameter, the recommended value of x is 3, to match the length of the gap Gateway requires to determine that a silent disconnect is deliberate.

To implement this:

1) Edit run_time/etc/pelsetup.def and add the parameter pre_resp_timer to the FT_FTP section. Example :

[FT_FTP]
trace=0
max_data=16000
timer=300
trace_auto=0
trace_data=0
trace_list=0
trace_mdt=0
trace_mem=0
trace_pdu=0
pre_resp_timer=3  

2) stop Gateway
3) execute the command : peluconf standalone rebuild -f
4) start Gateway.