Retrieve Email over SSL connection in VB.NET

In previous section, I introduced how to retrieve email from Exchange Server with WebDAV protocol. In this section, I will introduce how to retrieve email over SSL connection in VB.NET.

Introduction

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);

EAGetMail POP3 component supports both ways. Please see the following example codes:

For Exchange Web Service/WebDAV protocol, the SSL is based on HTTPS connection, so you just need to set SSLConnection property and simply ignore Port property. Notice: Exchange Web Service requires SSL connection by default.

[VB.NET Example - SSL/TLS]

' Retrieve email by normal TCP/IP without SSL connection
' POP3
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    False, ServerAuthType.AuthLogin, ServerProtocol.Pop3)

' IMAP4
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    False, ServerAuthType.AuthLogin, ServerProtocol.Imap4)

' Retrieve email over SSL connection with direct SSL.
' POP3 SSL
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    True, ServerAuthType.AuthLogin, ServerProtocol.Pop3)
oServer.Port = 995

' IMAP4 SSL
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    True, ServerAuthType.AuthLogin, ServerProtocol.Imap4)
oServer.Port = 993

' Retrieve email by SSL connection with STARTTLS or TLS command switching
' POP3 TLS
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    True, ServerAuthType.AuthLogin, ServerProtocol.Pop3)
oServer.Port = 110
oServer.SSLType = SSLConnectType.ConnectTLS

' IMAP4 STARTTLS
Dim oServer As New MailServer("myserveraddress", "myuser", "mypassword", _
    True, ServerAuthType.AuthLogin, ServerProtocol.Imap4)
oServer.Port = 143
oServer.SSLType = SSLConnectType.ConnectTLS


' Exchange WebDAV
Dim oServer As New MailServer("myserveraddress", _
    "myuser", "mypassword", False,  _
    ServerAuthType.AuthLogin, ServerProtocol.ExchangeWebDAV)

' Exchange Web Service SSL
Dim oServer As New MailServer("myserveraddress", _
    "myuser", "mypassword", True, _
    ServerAuthType.AuthLogin, ServerProtocol.ExchangeEWS)

' Exchange WebDAV SSL
Dim oServer As New MailServer("myserveraddress", _
    "myuser", "mypassword", True, _
    ServerAuthType.AuthLogin, ServerProtocol.ExchangeWebDAV)

Note

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

[VB.NET Example - Retrieve email from POP3 server over SSL on 995 port]

The following example codes demonstrate how to retrieve emails from POP3 server over SSL connection on 995 port. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

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

Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1
    Sub Main()
        ' Create a folder named "inbox" under current directory
        ' to save the email retrieved.
        Dim curpath As String = Directory.GetCurrentDirectory()
        Dim mailbox As String = [String].Format("{0}\inbox", curpath)

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

        Dim oServer As New MailServer("pop3.emailarchitect.net", _
            "test@emailarchitect.net", "testpassword", ServerProtocol.Pop3)
        Dim oClient As New MailClient("TryIt")

        ' Enable SSL connection,
        oServer.SSLConnection = True

        ' Set 995 SSL port
        oServer.Port = 995

        Try
            oClient.Connect(oServer)
            Dim infos As MailInfo() = oClient.GetMailInfos()
            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)

                ' Receive email from POP3 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 email file name based on date time.
                Dim d As System.DateTime = System.DateTime.Now
                Dim cur As New System.Globalization.CultureInfo("en-US")
                Dim sdate As String = d.ToString("yyyyMMddHHmmss", cur)
                Dim fileName As String = [String].Format("{0}\{1}{2}{3}.eml", _
                    mailbox, sdate, d.Millisecond.ToString("d3"), i)

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

                ' Mark email as deleted from POP3 server.
                oClient.Delete(info)
            Next

            ' Quit and purge emails marked as deleted from POP3 server.
            oClient.Quit()
        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

[VB.NET Example - Retrieve email from IMAP4 server over SSL on 993 port]

The following example codes demonstrate how to retrieve emails from IMAP4 server over SSL connection on 993 port. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

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

Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1
    Sub Main()
        ' Create a folder named "inbox" under current directory
        ' to save the email retrieved.
        Dim curpath As String = Directory.GetCurrentDirectory()
        Dim mailbox As String = [String].Format("{0}\inbox", curpath)

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

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

        ' Enable SSL connection,
        oServer.SSLConnection = True

        ' Set 993 SSL port
        oServer.Port = 993

        Try
            oClient.Connect(oServer)
            Dim infos As MailInfo() = oClient.GetMailInfos()
            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)

                ' Receive 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 email file name based on date time.
                Dim d As System.DateTime = System.DateTime.Now
                Dim cur As New System.Globalization.CultureInfo("en-US")
                Dim sdate As String = d.ToString("yyyyMMddHHmmss", cur)
                Dim fileName As String = [String].Format("{0}\{1}{2}{3}.eml", _
                    mailbox, sdate, d.Millisecond.ToString("d3"), i)

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

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

            ' Quit and purge emails marked as deleted from IMAP server.
            oClient.Quit()
        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

Next Section

At next section I will introduce how to download emails from Gmail account.

Appendix

Comments

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