邮件 信头分析

发送方
From: [e-mail]
//*它记录了这封邮件来自哪个或哪些人的地址,但并不一定是邮件的发送人,
To: [e-mail]                                        
//*收件人                                                         
Date: Tue, Mar 18 1998 15:36:24 GMT                                
//*日期                                         
X-mailer:Sendmail 8.9.0                                          
Subject: Greetings                                              
//*主题                                                          
接收方                                                        
当邮件服务器 mail.domain1.com 把邮件传到接收方的服务器 mail.domain2.com 时，接受方服务器会在信头上记录下有关的计算机信息，邮件的信头变成：                                               
Received: from client1.domain1.com (client1.domain1.com [111.11.1.1]) by mail.domain1.com (8.8.5) id 004A21; Tue, Mar 18 1998 15:3 7:24 GMT                                             
//*提供了邮件操作的电子轨迹,每一台接收到邮件的机器都会自动添加以“Received:”开始的那一行。如果你收的邮件有多个以它开头的行，表明这封邮件可 能是被转发或被退回的错误邮件。缩进的那一行是本行的继续。
From: [e-mail]                                        
To: [e-mail]                                         
Date: Tue, Mar 18 1998 15:36:24 GMT                             
Message-Id: <[e-mail]>        
//*邮件唯一标识符.                                              
X-mailer:Sendmail 8.9.0                                         
Subject: Greetings                                              
当收件人服务器mail.domain2.com 把邮件接收并存初下来，等待收件人来阅读时，邮件的信头将会再加入一条记录
Received: from mail.domain1.com (mail.domain1.com [111.11.1.0] ) by mail.domain2.com (8.8.5/8.7.2) with ESMTP id LAA20869; Tue, Mar 18 1998 15:39:44 GMT                                 
//*这封信是从一台自称为 mail.domain1.com 的机器上接收的；这台机器的IP 地址是[111.11.1.0]，真实名字就是标称名字 mail.domain1.com; 接收方的机器名称是 mail.domain2.com, 运行的邮件服务器是 Sendmail, 版本(8.8.5/8.7.2) 。接收方机器给邮件的编号是ESMTP id LAA20869， 接收到的时间是 Tue, Mar 18 1998 15:39:44 GMT。
Received: from client1.domain1.com (client1.domain1.com [111.11.1.1]) by mail.domain1.com (8.8.5) id 004A21; Tue, Mar 18 1998 15:37:24 GMT                                              
//*这条记录表明信件是由机器client1.domain1.com ( IP 地址是 [111.11.1.1]) 在Tue, Mar 18 1998 15:37:24 GMT交给mail.domain1.com，并赋给编号id 004A21。                                     
From: [e-mail]                                        
To: [e-mail]                                         
Date: Tue, Mar 18 1998 15:36:24 GMT                             
Message-Id: [e-mail]          
//*这是由发件方邮件服务器赋给这封邮件的编号。与其它编号不同，这个编号自始至终跟随邮件。
X-mailer:Sendmail 8.9.0                                         
Subject: Greetings                                              
Return-Path:        提供了邮件操作的电子轨迹,应提供给发送人一个回复路径.
Received:          提供了邮件操作的电子轨迹,每一台接收到邮件的机器都会自动添加以“Received:”开始的那一行。如果你收的邮件有多个以它开头的行，表明这封邮件可能是被转发或被退回的错误邮件。缩进的那一行是本行的继续。
From:             它记录了这封邮件来自哪个或哪些人的地址,但并不一定是邮件的发送人,
Sender:            如果存在的话应该总是包含实际邮件发送人的有效邮件地址.
X-organization:      以X-开始的字段是用于增加更多信息的”用户自定义”字段.
X-Phone:           同上                                         
Reply-to:           指出了这封信和回复地址.                     
Errors-to:           告诉Sendmail 应该将出错信息送到哪里        
To:                收件人                                       
Cc:                副本抄送                                    
Bcc:               匿名发送, Bcc行包含某些人地址,这些人接收这封邮件,但是收件人列表的其他人并不知道这一点.
Message-ID:        邮件唯一标识符.                               
Subject:            主旨                                        
Comment:          注释,很少用.                                  
Date:              日期                                          
Resent-From:       重发或转发邮件添加＂resent＂信头             
Resent-To:                                                      
Resent-Cc:                                                       
Resent-Bcc                                                      
Resent-Date:                                                    
Resent-Message-Id:                                               
Return-Receipt-To:  如果它是一个消息的信头中的一行,当这封邮件被投递给最终目的地时,一个返回收据被发送到这个信头行规定的地址,
Apparently-To:      当惟一的收信人信息在信封上时,它被添加到邮件中
Precedence:        它如果存在,会用后面给定的值来标明该项邮件的优先权值.
References:                                                     
In-Reply-To:                                                     
Keyword:                                                        
Full-Name:         用于填定发件人的全名