Occasional problems with Filezilla FTP login in IIBv9

Question

I have got an IIBv9 application which outputs files to a Filezilla FTP server using the standard FileOutput node and an FTP security identity. In most cases, it works perfectly. However, it occasionally fails to transfer a file producing an exception:

          (0x03000000:NameValue):File     = 'AbstractFileOutputNode.java' (CHARACTER)
          (0x03000000:NameValue):Line     = 809 (INTEGER)
          (0x03000000:NameValue):Function = 'transferToFtpServer' (CHARACTER)
          (0x03000000:NameValue):Type     = '' (CHARACTER)
          (0x03000000:NameValue):Name     = '' (CHARACTER)
          (0x03000000:NameValue):Label    = '' (CHARACTER)
          (0x03000000:NameValue):Catalog  = 'BIPmsgs' (CHARACTER)
          (0x03000000:NameValue):Severity = 3 (INTEGER)
          (0x03000000:NameValue):Number   = 3381 (INTEGER)
          (0x03000000:NameValue):Text     = '' (CHARACTER)
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = 'FileOutput' (CHARACTER)
          )
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = '(myFlowName)' (CHARACTER)
          )
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = '(host)' (CHARACTER)
          )
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = '(login)' (CHARACTER)
          )
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = 'USER =>response:  ReplyCode: 220' (CHARACTER)
          )
          (0x01000000:Name     ):Insert   = (
            (0x03000000:NameValue):Type = 5 (INTEGER)
            (0x03000000:NameValue):Text = 'FTP' (CHARACTER)

Filezilla logs only have the following lines:

(005433) 21.12.2020 7:42:29 - (not logged in) (192.168.15.104)> 220 Please visit https://filezilla-project.org/
(005433) 21.12.2020 7:42:35 - (not logged in) (192.168.15.104)> USER (login)
(005433) 21.12.2020 7:42:35 - (not logged in) (192.168.15.104)> 331 Password required for (login)
(005433) 21.12.2020 7:42:35 - (not logged in) (192.168.15.104)> disconnected.

The broker restart or the filezilla server restart seem to help overcome the issue, and the same file is transferred successfully. But I cannot understand what causes the troubles.

Answer 1

My understanding of the log is that there was a disconnection. The client re-connected, but the server expected a user login. The client didn't understand the demand and wanted to continue with upload. The result was that the upload just stopped.

One common reason for such an interruption is if the IP address of the client has changed. This can happen if the client's DHCP lease on the router has elapsed, and the same can happen for the ISP. But many other reasons are possible, too many to list.

The explanation of a momentary disconnection is supported by the poster's experience: "The broker restart or the filezilla server restart seem to help overcome the issue, and the same file is transferred successfully".