是什么导致接收 phpmailer 发送的邮件延迟 4 分钟？

Question

这是电子邮件标题：

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TSbA==
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8pdA==
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dkim=pass header.i=@chefsbutcher.co.il header.s=default header.b=sY81zHWu;
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for <[e-mail]>
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Date: Sun, 3 Nov 2019 17:08:27 +0200
To: [e-mail]
From: "קצביית השף" <[e-mail]>
Subject: כמעט אצלך! הזמנתך מקצביית השף בתהליך משלוח!
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正如你所看到的，跳3有4分钟的延迟(还有为什么跳中的from列是空的？(

是什么原因造成了这次延误？

Answer 1

4分钟的延迟是一种特定的反钓鱼隔离，会影响某些类型的带有按钮和链接的电子邮件。它与SMTP的工作方式无关
https://www.welivesecurity.com/2017/06/01/ongoing-phishing-fight-google-delay-delivery-suspicious-messages-enterprise-gmail-customers/

Answer 2

传递延迟只是SMTP工作方式的固有部分。与HTTP等协议不同的是，即使通过代理链，它们也会或多或少地立即连接并发生，SMTP发送的消息在旅途中的任何时候都可能被长时间搁置。在此期间，它们可能会被任何中间中继服务器写入磁盘，并在一段时间内被忽略，然后提取并在稍后重试传递。这可能在几秒钟内发生，而且经常发生，但你不能依赖它-SMTP中没有任何东西阻止它花天。

作为发送者，除了试图避免你可以控制的瓶颈之外，你几乎无法控制这一点，比如确保你通过一个连接良好的中继发送，该中继有着长期不发送垃圾邮件的历史。

像谷歌和雅虎这样的大型互联网服务提供商经常使用SMTP延迟发送(接收服务器会说"我现在很忙，稍后再来"(来限制他们出于某种原因不同意的发件人的速率，例如他们发送的邮件太多，使用的连接太多，或者收件人将邮件报告为垃圾邮件。

简而言之，调整你的期望；像这样的延误是很常见的，你所看到的是完全正常的。