Send Email over SSL/TLS in VB 6.0¶

In previous section, I introduced how to send email in a simple VB6 project. In this section, I will introduce how to send email over SSL/TLS connection in VB 6.0.

Sections:

SSL and TLS Introduction
TLS 1.2
[VB 6.0 - Send Email over SSL/TLS Setting - Example]
[VB 6.0 - Send email over implicit SSL on 465 port - Example]
[VB 6.0 - Send email over TLS (Explicit SSL) on 25 or 587 port - Example]
SMTP Setting for Gmail, Yahoo, Hotmail and Office 365

SSL and TLS Introduction¶

SSL connection encrypts data between the SMTP component and SMTP server to protects user, password and email content in TCP/IP level. Now this technology is commonly used and many SMTP servers are deployed with SSL such as Gmail, Yahoo and Hotmail. There are two ways to deploy SSL on SMTP server:

Explicit SSL (TLS)

Using STARTTLS command to switch SSL channel on normal SMTP port (25 or 587);
Implicit SSL

Deploying SSL on another port (465 or other port, you may query it from your server administrator

EASendMail SMTP component supports both ways. The connection can be specified by Mail.ConnectType property. Please see the following example code.

TLS 1.2¶

TLS is the successor of SSL, more and more SMTP servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, and you got connection error with SSL/TLS connection, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

[VB 6.0 - Send Email over SSL/TLS Setting - Example]¶

The following example codes demonstrates how to set SSL/TLS connection.

 Const ConnectNormal = 0
 Const ConnectSSLAuto = 1
 Const ConnectSTARTTLS = 2
 Const ConnectDirectSSL = 3
 Const ConnectTryTLS = 4

 ' Send email by normal TCP/IP without SSL connection
 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 25

 ' Send email by SSL connection with STARTTLS command switching
 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 25
 oSmtp.ConnectType = ConnectSTARTTLS

 ' Send email by SSL connection with direct SSL.
 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 465
 oSmtp.ConnectType = ConnectDirectSSL

 ' Send email by SSL/TLS connection with auto-detect.
 ' If port is 25 or 587, STARTTLS TLS will be used; otherwise direct SSL will be used.
 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 465
 oSmtp.ConnectType = ConnectSSLAuto

 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 25
 oSmtp.ConnectType = ConnectSSLAuto

' Try to send email by SSL/TLS connection, if server doesn't support SSL/TLS, normal TCP is used.
 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 25
 oSmtp.ConnectType = ConnectTryTLS

 oSmtp.ServerAddr = "localhost"
 oSmtp.ServerPort = 587
 oSmtp.ConnectType = ConnectTryTLS

Note

Remarks: All of samples in this section are based on first section: Send email in a simple VB 6.0 project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[VB 6.0 - Send email over implicit SSL on 465 port - Example]¶

The following example codes demonstrate how to send email over SSL connection on 465 port.

Note

To get the full sample projects, please refer to Samples section.

Const ConnectNormal = 0
Const ConnectSSLAuto = 1
Const ConnectSTARTTLS = 2
Const ConnectDirectSSL = 3
Const ConnectTryTLS = 4

Private Sub Command1_Click()

    Dim oSmtp As New EASendMailObjLib.Mail
    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 VB 6.0 project"
    ' Set email body
    oSmtp.BodyText = "this is a test email sent from VB 6.0 project, do not reply"

    ' Your SMTP server address
    oSmtp.ServerAddr = "smtp.emailarchitect.net"

    ' User and password for ESMTP authentication, if your server doesn't require
    ' User authentication, please remove the following codes.
    oSmtp.UserName = "test@emailarchitect.net"
    oSmtp.Password = "testpassword"

    ' Set SSL 465 port
    oSmtp.ServerPort = 465

    ' Set direct SSL connection
    oSmtp.ConnectType = ConnectSSLAuto

    MsgBox "start to send email ..."
    If oSmtp.SendMail() = 0 Then
        MsgBox "email was sent successfully!"
    Else
        MsgBox "failed to send email with the following error:" & oSmtp.GetLastErrDescription()
    End If

End Sub

[VB 6.0 - Send email over TLS (Explicit SSL) on 25 or 587 port - Example]¶

The following example codes demonstrate how to send email over TLS (STARTTLS command, Explicit SSL) connection on 25 port.

Note

To get the full sample projects, please refer to Samples section.

Const ConnectNormal = 0
Const ConnectSSLAuto = 1
Const ConnectSTARTTLS = 2
Const ConnectDirectSSL = 3
Const ConnectTryTLS = 4

Private Sub Command1_Click()

    Dim oSmtp As New EASendMailObjLib.Mail
    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 VB 6.0 project"
    ' Set email body
    oSmtp.BodyText = "this is a test email sent from VB 6.0 project, do not reply"

    ' Your SMTP server address
    oSmtp.ServerAddr = "smtp.emailarchitect.net"

    ' User and password for ESMTP authentication
    oSmtp.UserName = "test@emailarchitect.net"
    oSmtp.Password = "testpassword"

    ' Set 25 port, if your server uses 587 port, please change 25 to 587
    oSmtp.ServerPort = 25

    ' Set TLS connection
    oSmtp.ConnectType = ConnectSSLAuto

    MsgBox "start to send email ..."
    If oSmtp.SendMail() = 0 Then
        MsgBox "email was sent successfully!"
    Else
        MsgBox "failed to send email with the following error:" & oSmtp.GetLastErrDescription()
    End If

End Sub

SMTP Server SSL Certificate

To send email over SSL/TLS connection, you don’t need to install a certificate on your machine. The data is encrypted by server certificate public/private key pair.

SMTP Setting for Gmail, Yahoo, Hotmail and Office 365¶

Because most popluar email providers support or require SSL/TLS connection, so I will introduce specific setting for Gmail, Yahoo, Hotmail and Office 365 in the coming sections.

Next Section

At next section I will introduce how to send email using Gmail account in VB6.

Tutorial Index

Send Email over SSL/TLS in VB 6.0¶

SSL and TLS Introduction¶

TLS 1.2¶

[VB 6.0 - Send Email over SSL/TLS Setting - Example]¶

[VB 6.0 - Send email over implicit SSL on 465 port - Example]¶

[VB 6.0 - Send email over TLS (Explicit SSL) on 25 or 587 port - Example]¶

SMTP Setting for Gmail, Yahoo, Hotmail and Office 365¶

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