email - 为什么 RECEIVED 电子邮件标题似乎按时间顺序乱序？

Question

查看 header 时，似乎第二台接收邮件的服务器直到最终 header 中​​报告的送达日期之后才转发它。

在 c9mailgw11.amadis.com，报告的时间是 22:47:49 -0800 (PST)。但是，最终服务器 BY2PR0401MB0966.namprd04.prod.outlook.com 将时间报告为 06:46:08 +0000。

差异是由于简单的原因造成的，例如 amadis 继电器上的时钟坏了吗？

我已经编写了一个检测电子邮件延迟的脚本，当我遇到这样的异常情况时，我从这一跳到下一跳得到一个负值，我想了解为什么它们以这种方式排序，看看我是否有办法向前看。

任何人都可以提供见解吗？

**Received: from BY2PR0401MB0966.namprd04.prod.outlook.com (10.160.64.15) by
 CY1PR0401MB0971.namprd04.prod.outlook.com (10.160.160.17) with Microsoft SMTP
 Server (TLS) id 15.1.403.16 via Mailbox Transport; Wed, 17 Feb 2016 06:46:08**
 +0000
Received: from BN3PR0401CA0023.namprd04.prod.outlook.com (10.162.159.161) by
 BY2PR0401MB0966.namprd04.prod.outlook.com (10.160.64.15) with Microsoft SMTP
 Server (TLS) id 15.1.409.15; Wed, 17 Feb 2016 06:46:07 +0000
Received: from BN3NAM01FT022.eop-nam01.prod.protection.outlook.com
 (2a01:111:f400:7e41::207) by BN3PR0401CA0023.outlook.office365.com
 (2a01:111:e400:51d1::33) with Microsoft SMTP Server (TLS) id 15.1.409.15 via
 Frontend Transport; Wed, 17 Feb 2016 06:46:07 +0000
Received: from BAY004-MC1F22.hotmail.com (10.152.66.51) by
 BN3NAM01FT022.mail.protection.outlook.com (10.152.67.153) with Microsoft SMTP
 Server (TLS) id 15.1.409.7 via Frontend Transport; Wed, 17 Feb 2016 06:46:06
 +0000
Received: from mail2world.com ([209.67.128.125]) by BAY004-MC1F22.hotmail.com with Microsoft SMTPSVC(7.5.7601.23143);
     Tue, 16 Feb 2016 22:46:06 -0800
Received: from mail pickup service by mail2world.com with Microsoft SMTPSVC;
     Tue, 16 Feb 2016 22:46:04 -0800
ResentFrom: xxx@xxx.com
Return-Path: xxx@xxx.com
Received: from 216.163.188.203 unverified ([216.163.188.203]) by mwpop05oc.mail2world.com with Mail2World SMTP Server; 
    Tue, 16 Feb 2016 22:46:01 -0800
**Received: from sender153-mail.zoho.com (unknown [74.201.84.153])
    by c9mailgw11.amadis.com (Postfix) with ESMTP id A432C5B996A81
    for <xxx@xxx.com>; Tue, 16 Feb 2016 22:47:49 -0800 (PST)**
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; 
  s=zapps768; d=zoho.com; 
  h=content-type:mime-version:subject:to:from:date; 
  b=b6BP/HJmeP+ORBz043y8K0tUFE3u3c8tUZvDSHjfuH0zD84gax1wUlRdYGps/SBd7SnFHYT1Plps
    wRQOJoRp6hEMPerW6MSOL9psGWfNel4lnZwdtr7ujnuh54CTTEwV  
Received: from [192.168.10.1] (xxx.xxx.net [xx.xx.xx.xx]) by mx.zohomail.com
    with SMTPS id 1455691501828999.0688176107503; Tue, 16 Feb 2016 22:45:01 -0800 (PST)

Answer 1

这个问题的答案记录在 rfc5321, section 4.4 中。如下:

When an SMTP server receives a message for delivery or further
processing, it MUST insert trace ("time stamp" or "Received")
information at the beginning of the message content, as discussed in
Section 4.1.1.4.

This line MUST be structured as follows:

o The FROM clause, which MUST be supplied in an SMTP environment,SHOULD contain both (1) the name of the source host as presentedin the EHLO command and (2) an address literal containing the IPaddress of the source, determined from the TCP connection.

o The ID clause MAY contain an "@" as suggested in RFC 822, butthisis not required.

o If the FOR clause appears, it MUST contain exactly one entry, even when multiple RCPT commands have been given. Multiples raise some security issues and have been deprecated, seeSection 7.2.

An Internet mail program MUST NOT change or delete a Received: linethat was previously added to the message header section. SMTP
servers MUST prepend Received lines to messages; they MUST NOT changethe order of existing lines or insert Received lines in any other
location.