# File lib/em/protocols/smtpserver.rb, line 312
      def process_helo domain
        if receive_ehlo_domain domain.dup
          send_data "250 #{get_server_domain}\r\n"
          reset_protocol_state
          @state << :ehlo
        else
          send_data "550 Requested action not taken\r\n"
        end
      end