Delphi - Send email using MX DNS lookup - smart host¶

Installation¶

EASendMail is a SMTP component which supports all operations of SMTP/ESMTP protocols (RFC 821, RFC 822, RFC 2554). Before you can use the following example codes, you should download the EASendMail Installer and install it on your machine at first.

Add reference¶

To use EASendMail SMTP ActiveX Object in your Delphi project, the first step is “Add Unit file of EASendMail to your project”. Please go to C:\Program Files\EASendMail\Include\delphi or C:\Program Files (x86)\EASendMail\Include\delphi folder, find EASendMailObjLib_TLB.pas, and then copy this file to your project folder.

unit Unit1;

interface
// include EASendMailObjLib_TLB unit to your Delphi Project
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, EASendMailObjLib_TLB, StdCtrls;

You can also create “EASendMailObjLib_TLB.pas” manually like this:

• Delphi 7

  Please choose menu -> Project -> Import Type Library and select EASendMailObj ActiveX Object, click Create Unit, the reference of EASendMail ActiveX Object will be added to your project.

  

• Delphi XE

  If you use Delphi XE to import the Type library, Please choose menu -> Component -> Import Component -> Import Type Library -> and select EASendMailObj ActiveX Object -> have Generate Component Wrapper checked -> Create Unit.

Then you can start to use it in your Delphi Project.

Delphi - Send email using MX DNS lookup - smart host - example¶

The following example codes demonstrate sending email message using MX DNS lookup. In order to run it correctly, please change SMTP server, user, password, sender, recipient value to yours.

Unit Unit1;

Interface

Uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls, EASendMailObjLib_TLB; // add EASendMail Unit

Type
    TForm1 = Class(TForm)
        Button1: TButton;
        Procedure Button1Click(Sender: TObject);
    private
        { Private declarations }
    public
        { Public declarations }
    End;

const
  ConnectNormal = 0;
  ConnectSSLAuto = 1;
  ConnectSTARTTLS = 2;
  ConnectDirectSSL = 3;
  ConnectTryTLS = 4;

Var
    Form1: TForm1;

    Implementation

    {$R *.dfm}

Procedure TForm1.Button1Click(Sender: TObject);
Var
oSmtp : TMail;
Begin
    oSmtp := TMail.Create(Application);
    oSmtp.LicenseCode := 'TryIt';

    // Set your sender email address
    oSmtp.FromAddr := 'test@emailarchitect.net';

    // Add recipient email address
    oSmtp.AddRecipientEx('support@emailarchitect.net', 0);

    // Set email subject
    oSmtp.Subject := 'simple email from Delphi project';

    // Set email body
    oSmtp.BodyText := 'this is a test email sent from Delphi project, do not reply';

    // Do not set SMTP server address
    oSmtp.ServerAddr := '';

    ShowMessage('start to send email ...');

    If oSmtp.SendMail() = 0 Then
        ShowMessage('email was sent successfully!')
    Else
        ShowMessage('failed to send email with the following error: '
        + oSmtp.GetLastErrDescription());

End;

End.

With above code, if you get error like “5xx IP address rejected”, that means your IP address is blocked by the recipient’s SMTP server. You have to specify a SMTP server with user authentication to relay your email.

Important notice¶

If your machine doesn’t have a static IP address, then I don’t suggest that you send email directly.

• If your IP address is dynamic, most SMTP servers reject your connection due to anti-spam policy. We always suggest that your send email by a SMTP server that has a static internet IP address. When you relay email by your SMTP server, because you do user authentication at first before you send email to your SMTP server, so your SMTP server doesn’t reject your connection even your IP address is dynamic. Finally your SMTP server sends email to remote SMTP server. Because your SMTP server has a static IP, the email won’t be rejected by remote SMTP server.

  

• If you encountered a temporal SMTP error (4xx), you should retry to send email later. That means you have to write the code to handle retry. So if you have a static IP address, I suggest that you use EASendMail Component + EASendMail Service, EASendMail service can send email directly or send email with specified SMTP server in background and handle delivery retry automatically.

To learn more detail about EASendMail Serivce, please have a look at Work with EASendMail Service (Email Queuing).

32bit/x64 ActiveX DLL¶

Seperate builds of run-time dll for 32 and x64 platform

Distribution¶

• Standard EXE

  For VB6, C++, Delphi or other standard exe application, you can distribute EASendMailObj.dll with your application to target machine without COM-registration and installer. To learn more detail, please have a look at Registration-free COM with Manifest File.

• Script

  For ASP, VBScript, VBA, MS SQL Stored Procedure, you need to install EASendMail on target machine by EASendMail installer, both 32bit/x64 DLL are installed and registered.