我刚刚在 CentOS 7 上使用 Postfix 设置了一个新的邮件服务器，该机器充当两个域（domain1.com 和 domain2.com）的 mx。服务器的主机名是 domain1.com，并且具有正确的 PTR 记录集。两个域都将其唯一的 MX 记录指向 domain1，并且都具有正确的 DKIM 和 SPF 记录。
问题在于，从地址@domain2.com 发送的邮件始终被 GMail 标记为垃圾邮件，而从@domain1.com 发送的完全相同的邮件则不会被标记为垃圾邮件。
以下是 dig 输出的一些 DNS 记录。
域 1
domain1.com. 300 IN A 1.2.3.4
domain1.com. 300 IN MX 1 domain1.com.
domain1.com. 300 IN TXT "v=spf1 mx ~all"
default._domainkey.domain1.com 300 IN TXT "v=DKIM1\; k=rsa\; p=<blurp>"
1.2.3.4 的反向 DNS
4.3.2.1.in-addr.arpa. 3600 IN PTR domain1.com
域 2
domain2.com. 300 IN A 1.2.3.4
domain2.com. 300 IN MX 1 domain1.com.
domain2.com. 300 IN TXT "v=spf1 mx ~all"
default._domainkey.domain2.com. 300 IN TXT "v=DKIM1\; k=rsa\; p=<blurp>"
SMTP 服务器对 EHLO 做出如下响应：
220 domain1.com ESMTP Postfix
EHLO banana
250-domain1.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
同样，问题在于，从 @domain2.com 发送的完全相同的邮件被标记为垃圾邮件，但来自 @domain1.com 的邮件则没有。我尝试通过多个 DKIM 和 SPF 验证器运行整个设置，并且还对照多个黑名单检查了 IP。此外，我在 mxtoolbom.com 上运行了所有测试，这些工具均未报告任何问题。
以下是 GMail 看到的同一用户分别从 domain1.com 和 domain2.com 发送的两封电子邮件：
非垃圾邮件 (@domain1)
Delivered-To: [email protected]
Received: by 10.60.57.165 with SMTP id j5csp382145oeq;
Tue, 28 Oct 2014 06:11:12 -0700 (PDT)
X-Received: by 10.112.168.2 with SMTP id zs2mr3138752lbb.25.1414501871638;
Tue, 28 Oct 2014 06:11:11 -0700 (PDT)
Return-Path: <[email protected]>
Received: from domain1.com (domain1.com. [1.2.3.4])
by mx.google.com with ESMTP id lm8si2545487lac.7.2014.10.28.06.11.10
for <[email protected]>;
Tue, 28 Oct 2014 06:11:11 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates 1.2.3.4 as permitted sender) client-ip=1.2.3.4;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of [email protected] designates 1.2.3.4 as permitted sender) [email protected];
dkim=pass [email protected]
Received: by domain1.com (Postfix, from userid 1001)
id 7104140D41; Tue, 28 Oct 2014 14:11:10 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=domain1.com;
s=default; t=1414501870;
bh=6ycM+eq5HvFTqqe79TLije21S91XFijH+fOKPHMU5Zc=;
h=From:Subject:Date:To;
b=<blurp>
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on domain2.com
X-Spam-Level:
X-Spam-Status: No, score=-1.1 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED,
DKIM_VALID,DKIM_VALID_AU,URIBL_BLOCKED autolearn=ham version=3.3.2
Received: from [192.168.178.63] (dsl.provider.com [100.100.100.100])
by domain1.com (Postfix) with ESMTPSA id 726E140D09
for <[email protected]>; Tue, 28 Oct 2014 14:11:05 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=domain1.com;
s=default; t=1414501865;
bh=6ycM+eq5HvFTqqe79TLije21S91XFijH+fOKPHMU5Zc=;
h=From:Subject:Date:To;
b=<blurp>
From: That Guy <[email protected]>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Subject: Yellow Bananas
Message-Id: <[email protected]>
Date: Tue, 28 Oct 2014 14:11:05 +0100
To: [email protected]
Mime-Version: 1.0 (Mac OS X Mail 8.0 \(1990.1\))
X-Mailer: Apple Mail (2.1990.1)
Hi,
Do not forget to buy some bananas!
标记为 span (@domain2.com)
Delivered-To: [email protected]
Received: by 10.60.57.165 with SMTP id j5csp382123oeq;
Tue, 28 Oct 2014 06:11:01 -0700 (PDT)
X-Received: by 10.112.167.130 with SMTP id zo2mr4018217lbb.4.1414501861369;
Tue, 28 Oct 2014 06:11:01 -0700 (PDT)
Return-Path: <[email protected]>
Received: from domain1.com (domain1.com. [1.2.3.4])
by mx.google.com with ESMTP id mj1si2507360lbc.40.2014.10.28.06.11.00
for <[email protected]>;
Tue, 28 Oct 2014 06:11:01 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates 1.2.3.4 as permitted sender) client-ip=1.2.3.4;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of [email protected] designates 1.2.3.4 as permitted sender) [email protected];
dkim=pass [email protected]
Received: by domain1.com (Postfix, from userid 1001)
id E816D40D41; Tue, 28 Oct 2014 14:10:59 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=domain2.com;
s=default; t=1414501859;
bh=6ycM+eq5HvFTqqe79TLije21S91XFijH+fOKPHMU5Zc=;
h=From:Subject:Date:To;
b=<blurp>
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on domain2.com
X-Spam-Level:
X-Spam-Status: No, score=-1.1 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED,
DKIM_VALID,DKIM_VALID_AU,URIBL_BLOCKED autolearn=ham version=3.3.2
Received: from [192.168.178.63] (dsl.provider.com [100.100.100.100])
by domain1.com (Postfix) with ESMTPSA id F326840D09
for <[email protected]>; Tue, 28 Oct 2014 14:10:54 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=domain2.com;
s=default; t=1414501855;
bh=6ycM+eq5HvFTqqe79TLije21S91XFijH+fOKPHMU5Zc=;
h=From:Subject:Date:To;
b=<blurp>
From: That Guy <[email protected]>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Subject: Yellow Bananas
Message-Id: <[email protected]>
Date: Tue, 28 Oct 2014 14:10:53 +0100
To: [email protected]
Mime-Version: 1.0 (Mac OS X Mail 8.0 \(1990.1\))
X-Mailer: Apple Mail (2.1990.1)
Hi,
Do not forget to buy some bananas!
根据 Google 的说法，阻止第二封邮件的原因是：“为什么这封邮件在垃圾邮件中？它与我们的垃圾邮件过滤器检测到的邮件类似。了解更多”，这是https://support.google.com/mail/answer/1366858?hl=en&expand=5。
我已经花了好几个小时了，但似乎还是搞不清楚。我按照 Google 在其批量电子邮件指南中推荐的方法做了所有事情。