The following vb.net example codes demonstrate how to send email using Gmail SMTP server.
Gmail SMTP Server
Gmail SMTP server address is
smtp.gmail.com. It requires implicit SSL or explicit
SSL (TLS) connection, and you should use your Gmail email address as the user name
for ESMTP authentication.
To help keep your account secure, starting May 30, 2022, Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password.
Therefore, you should sign in using App Passwords.
App Password is a 16-digit passcode that gives a less secure app or device permission
to access your Google Account.
App Passwords can only be used with accounts that have 2-Step Verification turned on.
You need to use
App Password instead of the user password for user authentication.
Another solution is Gmail OAUH, please see Gmail SMTP OAUTH section.
Before you can use the following codes, please download EASendMail SMTP Component and install it on your machine at first. Full sample proejcts are included in this installer.
Install from NuGet
You can also install the run-time assembly by NuGet. Run the following command in the NuGet Package Manager Console:
If you install it by NuGet, no sample projects are installed, only .NET assembly is installed.
To use EASendMail SMTP Component in your project, the first step is
of EASendMail to your project. Please create or open your project with Visual Studio,
then go to
Add Reference ->
Browse..., and select
Installation Path\Lib\net[version]\EASendMail.dll from your disk, click
OK, the reference of EASendMail
will be added to your project, and you can start to use it to send email
in your project.
Because EASendMail has separate builds for .Net Framework, please refer to the following table and choose the correct dll.
Separate builds of run-time assembly for .NET Framework 1.1, 2.0, 3.5, 4.0, 4.5, 4.6.1, .NET Core 3.1, .NET 5.0, .NET Standard 2.0 and .NET Compact Framework 2.0, 3.5.
|File||.NET Framework Version|
Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
Built with .NET Framework 4.6.1
It requires .NET Framework 4.6.1 or later version.
Built with .NET Core 3.1
It requires .NET Core 3.1 or later version.
Built with .NET 5.0
It requires .NET 5.0 or later version.
Built with .NET Standard 2.0
It requires .NET Standard 2.0 or later version.
Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
Built with .NET Compact Framework 3.5
It requires .NET Compact Framework 3.5 or later version.
The following example codes demonstrate sending email using Gmail SMTP server.
In order to run it correctly, please change
recipient value to yours.
To get full sample projects, please download and install EASendMail on your machine.
Imports EASendMail 'Add EASendMail Namespace Module Module1 Sub Main() Try Dim oMail As New SmtpMail("TryIt") ' Your gmail email address oMail.From = "firstname.lastname@example.org" ' Set recipient email address, please change it to yours oMail.To = "email@example.com" ' Set email subject oMail.Subject = "test email from gmail account over SSL" ' Set email body oMail.TextBody = "this is a test email sent from VB.NET project with gmail" 'Gmail SMTP server address Dim oServer As New SmtpServer("smtp.gmail.com") ' Gmail user authentication should use your ' Gmail email address as the user name. ' For example: your email is "firstname.lastname@example.org", then the user should be "email@example.com" oServer.User = "gmailid" ' Create app password in Google account ' https://support.google.com/accounts/answer/185833?hl=en oServer.Password = "your app password" ' If you want to use direct SSL 465 or 587 port, ' please add this line, otherwise TLS will be used. ' oServer.Port = 465 ' detect SSL/TLS automatically oServer.ConnectType = SmtpConnectType.ConnectSSLAuto Console.WriteLine("start to send email over SSL ...") Dim oSmtp As New SmtpClient() oSmtp.SendMail(oServer, oMail) Console.WriteLine("email was sent successfully!") Catch ep As Exception Console.WriteLine("failed to send email with the following error:") Console.WriteLine(ep.Message) End Try End Sub End Module
The Gmail IMAP and SMTP servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Gmail Web OAuth instead of inputting user and password directly in application. This way is more secure, but a little bit complex.
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, you need to
enable TLS 1.2 protocol in your operating system like this: