Dim sessionOptions As New SessionOptions
    With sessionOptions
    .Protocol = Protocol.Sftp
    .HostName = url
    .UserName = user
    .PortNumber = port
    If pass <> String.Empty Then
      .Password = pass
    End If
    If privatekeyfile <> String.Empty Then
      .SshPrivateKeyPath = privatekeyfile
    End If
End With

sessionOptions.GiveUpSecurityAndAcceptAnySshHostKey = True