WSAECONNRESET An existing connection was forcibly closed by the remote host.

Explains the meaning of the "WSAECONNRESET An existing connection was forcibly closed by the remote host." error and demonstrates a way to reproduce it by setting the "No Transfer Timeout" setting on a FileZilla FTP server to a very small value.

Download: Chilkat .NET Assemblies

Dim ftp As New Chilkat.Ftp2()

Dim success As Boolean

'  Any string unlocks the component for the 1st 30-days.
success = ftp.UnlockComponent("Anything for 30-day trial")
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


ftp.Hostname = "192.168.1.108"
ftp.Username = "myLogin"
ftp.Password = "myPassword"

'  Connect and login to the FTP server.
success = ftp.Connect()
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


ftp.Passive = true

'  In this example, we've set the FileZilla FTP Server's
'  "No Transfer Timeout" to 5 seconds.  This is a setting
'  on the FTP server (not in the Chilkat FTP component).
'  It causes the server to disconnect from the client after
'  5 seconds of no upload or download activity.  As you'll see,
'  sending commands over the control channel, such as
'  NOOP (no-operation) commands will have no effect.
'  It is an upload, download, or directory listing that is required.

'  This code will wait 10 seconds before proceeding with
'  the PutFile.  This should be enough time for the FileZilla
'  server to disconnect.
Dim i As Long
For i = 0 To 10
    '  Sleep for 1 second
    ftp.SleepMs(1000)

    '  Send a NOOP command to the FTP server.
    '  After about 5 iterations, it should fail and the LastErrorText
    '  will contain this message:
    '  WSAECONNRESET An existing connection was forcibly closed by the remote host.
    success = ftp.Noop()
    If (success <> true) Then
        TextBox1.Text = TextBox1.Text & ftp.LastErrorText & vbCrLf
        Exit For
    End If

Next

'  What happens if we try to upload a file without an existing
'  connection?
'  Let's do it and find out...

'  Upload a file.
Dim localFilename As String
localFilename = "c:/temp/hamlet.xml"
Dim remoteFilename As String
remoteFilename = "hamlet.xml"

success = ftp.PutFile(localFilename,remoteFilename)
If (success <> true) Then

    '  In Active mode (i.e. non-passive), we get this error:
    '  "Failed to get socket's IP address. Socket may already be disconnected."
    '  In Passive mode, we'll get this error:
    '  " No socket exists for sending (2)"
    TextBox1.Text = TextBox1.Text & ftp.LastErrorText & vbCrLf
    Exit Sub
End If


ftp.Disconnect()

MsgBox("File Uploaded!")