Gmail收到的完整邮件（邮箱、服务器ip和主机都被替换了）：
Delivered-To: <myemail>
Received: by 10.180.24.132 with SMTP id u4cs216052wif;
Thu, 20 Oct 2011 03:22:03 -0700 (PDT)
Received: by 10.14.9.165 with SMTP id 37mr1294749eet.51.1319106122223;
Thu, 20 Oct 2011 03:22:02 -0700 (PDT)
Return-Path: <www-data@<serverdomain>>
Received: from <serverdomain> (<serverdomain>. [<serverip>])
by mx.google.com with ESMTP id s55si2781134ees.156.2011.10.20.03.22.02;
Thu, 20 Oct 2011 03:22:02 -0700 (PDT)
Received-SPF: pass (google.com: domain of www-data@<serverdomain> designates <serverip> as permitted sender) client-ip=<serverip>;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of www-data@<serverdomain> designates <serverip> as permitted sender) smtp.mail=www-data@<serverdomain>
Received: by <serverdomain> (Postfix, …