Delphi DLL

FTP over Implicit TLS (Ssl, AuthSsl, AutoFix)

Demonstrates the SSL/TLS connection-mode properties Ssl, AuthSsl, and AutoFix. Setting Ssl true selects implicit FTPS, in which TLS begins immediately after the TCP connection on port 990.

Background: FTP has two ways to add TLS: implicit (this example) starts encrypted from the first byte on a dedicated port, 990; explicit (via AuthTls) connects in the clear on port 21 and issues AUTH TLS to upgrade. Explicit is the modern standard; implicit persists mainly for legacy servers. AuthSsl is an obsolete AUTH SSL variant to avoid. AutoFix, on by default, infers the mode from the port — disable it when you set these properties explicitly so it does not override your choice.

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var
success: Boolean;
ftp: HCkFtp2;

begin
success := False;

ftp := CkFtp2_Create();

CkFtp2_putHostname(ftp,'ftp.example.com');
CkFtp2_putUsername(ftp,'myFtpLogin');

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
CkFtp2_putPassword(ftp,'myPassword');

//  Ssl = 1 selects IMPLICIT FTPS: TLS begins immediately after the TCP connection, before
//  the greeting.  Port 990 is conventional for implicit FTPS.  Ssl takes priority over AuthTls
//  and AuthSsl.
CkFtp2_putSsl(ftp,True);
CkFtp2_putPort(ftp,990);

//  AuthSsl selects the legacy AUTH SSL command and is very uncommon -- use AuthTls (explicit
//  FTPS) for modern servers instead.  Left 0 here.
CkFtp2_putAuthSsl(ftp,False);

//  AutoFix (default 1) automatically adjusts Ssl/AuthTls/AuthSsl based solely on the Port
//  (21 or 990).  Disable it when setting these properties explicitly, as here.
CkFtp2_putAutoFix(ftp,False);

success := CkFtp2_Connect(ftp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
    Exit;
  end;

Memo1.Lines.Add('Connected using implicit FTPS.');

success := CkFtp2_Disconnect(ftp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
    Exit;
  end;

CkFtp2_Dispose(ftp);