SSL POP3 with Certificates

Demonstrates how to use a client-side certificate with an SSL connection to a POP3 server. Also demonstrates how to get the POP3 server's SSL certificate.

Download Chilkat .NET for 2.0 / 3.5 Framework

Download Chilkat .NET for 1.0 / 1.1 Framework

'  The mailman object is used for receiving (POP3)
'  and sending (SMTP) email.
Dim mailman As New Chilkat.MailMan()

'  Any string argument automatically begins the 30-day trial.
Dim success As Boolean
success = mailman.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("Component unlock failed")
    Exit Sub
End If


'  Set the GMail account POP3 properties.
mailman.MailHost = "pop.gmail.com"
mailman.PopUsername = "chilkat.support"
mailman.PopPassword = "****"
mailman.PopSsl = true
mailman.MailPort = 995

'  Use our certificate, which is already installed
'  in our current-user certificate store on the computer.
Dim clientCert As New Chilkat.Cert()
success = clientCert.LoadByCommonName("Chilkat Software, Inc.")
If (success <> true) Then
    MsgBox(clientCert.LastErrorText)
    Exit Sub
End If

'  Note: The GMail POP3 server does not require that you
'  have a client cert.  This example only demonstrates
'  how you may use a client certificate.  Typically,
'  higher-security systems may require a client-side SSL cert.
mailman.SetSslClientCert(clientCert)

'  Establish a POP3 connection:
success = mailman.Pop3BeginSession()
If (success <> true) Then
    MsgBox(mailman.LastErrorText)
    Exit Sub
End If

'  Let's look at the LastErrorText to see the details
'  of the successful connection.  We should see our cert:
TextBox1.Text = TextBox1.Text & mailman.LastErrorText & vbCrLf

'  OK, now examine the server's cert:
Dim serverCert As Chilkat.Cert
serverCert = mailman.GetPop3SslServerCert()
If (serverCert Is Nothing ) Then
    MsgBox("No server cert available.")
Else
    TextBox1.Text = TextBox1.Text & "Server SSL certificate:" & vbCrLf
    TextBox1.Text = TextBox1.Text & serverCert.SubjectDN & vbCrLf

    '  Was the server certificate verified?
    '  It's not necessarily an error if the SSL Server cert is not verified.
    If (mailman.Pop3SslServerCertVerified = true) Then
        TextBox1.Text = TextBox1.Text & "Server SSL certificate was verified." & vbCrLf
    Else
        TextBox1.Text = TextBox1.Text & "Server SSL certificate was NOT verified!" & vbCrLf
    End If

End If