69、电子邮件系统：SMTP协议、设计与别名管理全解析

电子邮件系统：SMTP协议、设计与别名管理全解析

1. 邮件头部信息分析

在邮件传输过程中，邮件头部包含了众多关键信息，但这些信息可能存在被伪造的风险。例如，有这样一封邮件：

Received-SPF: neutral (google.com: 63.173.189.2 is neither permitted nor denied 
by best guess record for domain of smotheringl39@sherman.dp.ua) client-
ip=63.173.189.2;
Authentication-Results: mx.google.com; spf=neutral (google.com: 63.173.189.2 is 
neither permitted nor denied by best guess record for domain of 
smotheringl39@sherman.dp.ua) smtp.mail=smotheringl39@sherman.dp.ua
Received: from SpeedTouch.lan (187-10-167-249.dsl.telesp.net.br 
[187.10.167.249] (may be forged)) by mail-relay.atrust.com …
Received: from 187.10.167.249 by relay2.trifle.net; Mon, 19 Oct 2009 13:59: …
From: "alert@atrust.com" <alert@atrust.com>
To: