使用 indy 组件 delphi xe2 SSL 协商失败发送电子邮件

Question

I tried with Indy component to send email in XE2, and it works fine on my laptop that I compiled my project on.

But if I take my exe project to another PC, it shows an error message

Connection closed gracefully

or, sometimes I get

SSL Negotiation failed

Actually I tried many times to solve my problem, but I can't.

This is my code - where is my mistake? I need a practical solution.

procedure Gmail(username, password, totarget, subject, body :string);
var
   DATA : TIdMessage;
   SMTP : TIdSMTP;
   SSL : TIdSSLIOHandlerSocketOpenSSL;
   result:Boolean;
begin
   try
      SMTP := TIdSMTP.Create(nil);
      DATA := TIdMessage.Create(nil);
      SSL := TIdSSLIOHandlerSocketOpenSSL.Create(nil);

      SSL.Destination := 'smtp.gmail.com:587';
      SSL.Host := 'smtp.gmail.com';
      //  SSL.MaxLineAction.maException;
      SSL.Port:= 587;
      SSL.SSLOptions.Method := sslvTLSv1;
      SSL.SSLOptions.Mode := sslmUnassigned;
      SSL.SSLOptions.VerifyMode :=  [];
      SSL.SSLOptions.VerifyDepth := 0;

      DATA.From.Address := username;
      DATA.Recipients.EMailAddresses := totarget;
      DATA.Subject := subject;
      DATA.Body.Text := body;

      if FileExists('D:\Test1.txt') then
         TIdAttachmentFile.Create(DATA.MessageParts, 'D:\Test1.txt');

      SMTP.IOHandler := SSL;
      SMTP.Host := 'smtp.live.com';
      SMTP.Port := 587 ;
      SMTP.Username := username;
      SMTP.Password := password;
      //  SMTP.SASLMechanisms;
      SMTP.UseTLS := utUseExplicitTLS;

      try
         try
           SMTP.Connect;
           SMTP.Send(DATA);
           Result := True;
         except
           on E:Exception do
           begin
               ShowMessage('Cannot send E-Mail: ' + E.Message);
               Result := False;
           end;
         end;
      finally
         if SMTP.Connected then SMTP.Disconnect;
      end;
  except
    on E : Exception do
    begin
      ShowMessage('Error in the function SendEmailDelphi: ' + E.Message);
      Result := False;
    end;
  end;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
Timer1.Enabled:= True;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
mail_username := 'email@gmail.com';
mail_password := 'pass';
mail_to := 'email@gmail.com';
mail_subject := 'Text email from Delphi project';
mail_body := 'this is a test email sent from Delphi project, do not reply';

 try
   begin
     Gmail(mail_username, mail_password, mail_to , mail_subject, mail_body);
   end;
 finally

 end;
end;

Answer 1

DO NOT set the SSL.Destination , SSL.Host , or SSL.Port properties manually! TIdTCPClient.Connect() handles that for you. Besides, don't you think it's odd that you are setting SSL.Destination/Host to smtp.gmail.com but are setting SMTP.Host to smtp.live.com instead? Gmail and Live are not the same service provider.

Also, SSL.SSLOptions.Mode should be set to sslmClient instead of sslmUnassigned . Not too important, TIdSSLIOHandlerSocketOpenSSL will simply flip it when it configures the connection. But you should do it anyway, since you know your code is acting as a client.

And lastly, try setting SMTP.UseTLS before setting SMTP.Port , as setting UseTLS may change the Port , so you want to make sure you are really connecting to the correct port you are expecting.

With that said, the SSL Negotiation failed error means the TLS handshake was started but failed part-way through the negotiation. Try assigning handlers to TIdSSLIOHandlerSocketOpenSSL 's OnStatusInfo/Ex events to see how far the handshake is actually getting. And if you are using a relatively modern version of Indy 10, try looking at the raised exception's InnerException property, it might give you a clue as to what went wrong before the EIdTLSClientTLSHandShakeFailed exception was raised afterwards.