# File lib/facets/more/smtp_tls.rb, line 6
  def do_start(helodomain, user, secret, authtype)
    raise IOError, 'SMTP session already started' if @started
    check_auth_args user, secret, authtype if user or secret

    sock = timeout(@open_timeout) { TCPSocket.open(@address, @port) }
    @socket = Net::InternetMessageIO.new(sock)
    @socket.read_timeout = 60 #@read_timeout

    check_response(critical { recv_response() })
    do_helo(helodomain)

    if starttls
      raise 'openssl library not installed' unless defined?(OpenSSL)
      ssl = OpenSSL::SSL::SSLSocket.new(sock)
      ssl.sync_close = true
      ssl.connect
      @socket = Net::InternetMessageIO.new(ssl)
      @socket.read_timeout = 60 #@read_timeout
      do_helo(helodomain)
    end

    authenticate user, secret, authtype if user
    @started = true
  ensure
    unless @started
      # authentication failed, cancel connection.
      @socket.close if not @started and @socket and not @socket.closed?
      @socket = nil
    end
  end