PowerShell

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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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  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.

$mailman = New-Object Chilkat.MailMan

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

#  Load the client certificate (with its private key) from a PFX file.
$cert = New-Object Chilkat.Cert
$success = $cert.LoadPfxFile("qa_data/certs/client.pfx","pfx_password")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

#  Use this certificate to identify the client during the TLS handshake.
$success = $mailman.SetSslClientCert($cert)
if ($success -eq $false) {
    $($mailman.LastErrorText)
    exit
}

$success = $mailman.VerifySmtpLogin()
if ($success -eq $false) {
    $($mailman.LastErrorText)
    exit
}

$("Connected using a TLS client certificate.")

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