Lua

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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Lua

local chilkat = require("chilkat")

-- 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.

local mailman = chilkat.MailMan.new()

-- Configure the SMTP server connection.
mailman.smtp_host = "smtp.example.com"
mailman.smtp_port = 465
mailman.smtp_ssl = true
mailman.smtp_username = "user@example.com"
mailman.smtp_password = "myPassword"

-- Load the client certificate (with its private key) from a PFX file.
local cert = chilkat.Cert.new()
local success = cert:load_pfx_file("qa_data/certs/client.pfx", "pfx_password")
if not success then
    print(cert.last_error_text)
    return
end

-- Use this certificate to identify the client during the TLS handshake.
success = mailman:set_ssl_client_cert(cert)
if not success then
    print(mailman.last_error_text)
    return
end

success = mailman:verify_smtp_login()
if not success then
    print(mailman.last_error_text)
    return
end

print("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.