Classic ASP

Use a TLS Client Certificate

Demonstrates the Chilkat MailMan.SetSslClientCert method, which sets the client-side certificate to use for SSL/TLS connections. This is typically not required — most SSL/TLS connections authenticate the server only. This example loads a client certificate from a PFX and uses it when connecting.

Background: In an ordinary TLS handshake only the server presents a certificate, and the client proves who it is later with a password. Mutual TLS adds a second leg: the client also presents a certificate, so it is authenticated cryptographically at the transport layer. Some corporate or high-security mail servers require this. Because the client must prove possession of the key, the certificate needs its private key — hence loading from a PFX.

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Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

'  Demonstrates the MailMan.SetSslClientCert method, which sets the client-side certificate
'  to use for SSL/TLS connections.  This is typically not required -- most SSL/TLS
'  connections authenticate the server only.

set mailman = Server.CreateObject("Chilkat.MailMan")

'  Configure the SMTP server connection.
mailman.SmtpHost = "smtp.example.com"
mailman.SmtpPort = 465
mailman.SmtpSsl = 1
mailman.SmtpUsername = "user@example.com"
mailman.SmtpPassword = "myPassword"

'  Load the client certificate (with its private key) from a PFX file.
set cert = Server.CreateObject("Chilkat.Cert")
success = cert.LoadPfxFile("qa_data/certs/client.pfx","pfx_password")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
End If

'  Use this certificate to identify the client during the TLS handshake.
success = mailman.SetSslClientCert(cert)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( mailman.LastErrorText) & "</pre>"
    Response.End
End If

success = mailman.VerifySmtpLogin()
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( mailman.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "Connected using a TLS client certificate.") & "</pre>"

'  Note: The path "qa_data/certs/client.pfx" is a relative local filesystem path,
'  relative to the current working directory of the running application.

%>
</body>
</html>