VB.NET - Retrieve Email over TLS from IMAP4 Server

The following vb.net example codes demonstrate how to retrieve email over TLS connection from IMAP4 server. This sample downloads emails from IMAP4 server and deletes the email after the email is retrieved.

SSL and TLS

SSL connection encrypts data between the email component and POP3 server or IMAP4 server to protect user, password and email content in TCP/IP level. Now this technology is commonly used and many email servers are deployed with SSL such as Gmail, Yahoo and Hotmail.

There are two ways to deploy SSL on email server:

  • Implicit SSL

    Deploying SSL on another port (POP3: 995 port or IMAP4: 993 port) directly. This is most common way.

  • Explicit SSL (TLS)

    Using STARTTLS or STLS command to switch SSL channel on normal port (POP3: 110 port or IMAP4: 143 port);

TLS 1.2

TLS is the successor of SSL, EAGetMail supports SSL 3.0/TLS1.0 - 1.2 very well. In EAGetMail, ConnectTLS doesn’t mean TLS encryption, it means TLS command in POP3/IMAP protocol.

You don’t have to set any property to enable TLS 1.2 encryption. If your server requires TLS 1.2 encryption, TLS 1.2 encryption is used automatically with ConnectTLS, ConnectSSL or ConnectSSLAuto.

To enable TLS 1.2 on some legacy systems, you have to install required update/packages:

Enable TLS 1.2 on Windows XP/2003/2008/7/2008 R2

TLS command can switch normal IMAP4 connection to SSL connection.

Installation

Before you can use the following sample codes, you should download the EAGetMail Installer and install it on your machine at first. Full sample projects 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:

Install-Package EAGetMail

Note

If you install it by NuGet, no sample projects are installed, only .NET assembly is installed.

Add Reference

To use EAGetMail POP3 & IMAP Component in your project, the first step is “Add reference of EAGetMail to your project”. Please create or open your project with Visual Studio, then go to menu -> Project -> Add Reference -> .NET -> Browse..., and select Installation path\Lib\[netversion]\EAGetMail.dll, click Open-> OK, the reference will be added to the project, you can start to use it to retrieve email and parse email in your project.

add reference in c#/vb.net/managed c++/cli

.NET Assembly

Because EAGetMail 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, 4.61, .NET Core 2.1 and .Net Compact Framework 2.0, 3.5.

File .NET Framework Version
Lib\net11\EAGetMail.dll Built with .NET Framework 1.1
It requires .NET Framework 1.1, 2.0, 3.5 or later version.
Lib\net20\EAGetMail.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
Lib\net35\EAGetMail.dll Built with .NET Framework 3.5
It requires .NET Framework 3.5 or later version.
Lib\net40\EAGetMail.dll Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
Lib\net45\EAGetMail.dll Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
Lib\net461\EAGetMail.dll Built with .NET Framework 4.6.1
It requires .NET Framework 4.6.1 or later version.
Lib\netcoreapp2.1\EAGetMail.dll Built with .NET Core 2.1
It requires .NET Core 2.1 or later version.
Lib\net20-cf\EAGetMail.dll Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
Lib\net35-cf\EAGetMail.dll Built with .NET Compact Framework 3.5
It requires .NET Compact Framework 3.5 or later version.

VB.NET - Retrieve Email over TLS from IMAP4 Server - Exmaple

The following example codes demonstrate retrieving email over TLS connection from IMAP4 server. In order to run it correctly, please change email server, user, password, folder, file name value to yours.

Note

To get full sample projects, please download and install EAGetMail on your machine.

Imports System.Globalization
Imports System.Text
Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1

    Function _generateFileName(ByVal sequence As Integer) As String
        Dim currentDateTime As DateTime = DateTime.Now
        Return String.Format("{0}-{1:000}-{2:000}.eml",
                            currentDateTime.ToString("yyyyMMddHHmmss", New CultureInfo("en-US")),
                            currentDateTime.Millisecond,
                            sequence)
    End Function

    Sub Main()

        Try
            ' Create a folder named "inbox" under current directory
            ' to save the email retrieved.
            Dim localInbox As String = String.Format("{0}\inbox", Directory.GetCurrentDirectory())

            ' If the folder is not existed, create it.
            If Not Directory.Exists(localInbox) Then
                Directory.CreateDirectory(localInbox)
            End If

            Dim oServer As New MailServer("imap.emailarchitect.net",
                        "test@emailarchitect.net",
                        "testpassword",
                        ServerProtocol.Imap4)

            ' Enable SSL Connection
            oServer.SSLConnection = True

            ' Set 143 IMAP4 Port
            oServer.Port = 143

            ' Set TLS connection type
            oServer.SSLType = SSLConnectType.ConnectTLS

            Console.WriteLine("Connecting server ...")

            Dim oClient As New MailClient("TryIt")
            oClient.Connect(oServer)

            Dim infos As MailInfo() = oClient.GetMailInfos()
            Console.WriteLine("Total {0} email(s)", infos.Length)

            For i As Integer = 0 To infos.Length - 1
                Dim info As MailInfo = infos(i)
                Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",
                        info.Index, info.Size, info.UIDL)

                ' Retrieve email from IMAP server
                Dim oMail As Mail = oClient.GetMail(info)

                Console.WriteLine("From: {0}", oMail.From.ToString())
                Console.WriteLine("Subject: {0}" & vbCr & vbLf, oMail.Subject)

                ' Generate an unqiue email file name based on date time.
                Dim fileName As String = _generateFileName(i + 1)
                Dim fullPath As String = String.Format("{0}\{1}", localInbox, fileName)

                ' Save email to local disk
                oMail.SaveAs(fullPath, True)

                ' Mark email as deleted from IMAP server.
                oClient.Delete(info)

            Next

            ' Quit and expunge emails marked as deleted from IMAP server.
            oClient.Quit()
            Console.WriteLine("Completed!")

        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

Appendix

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