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Accepted
mr.b
Asked: 2011-06-17 23:55:43 +0800 CST

Mail classified as spam, but passes SPF and DKIM

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I have configured Postfix to be responsible for subdomain.example.com (google apps is responsible for example.com so I didn't want to mix the two).

As I mentioned in question title, SPF and DKIM always pass when I send mail locally from that host ($ mail [email protected]), but mails still end up in Spam folder.

The only thing missing is reverse DNS setup for subdomain.example.com and IP it's sending from, but I figured it won't matter, since SPF includes a:ip.add.re.ss, and since SPF passes...

Any ideas what else could I do to get them into inbox?

UPDATE: problem was instantly resolved as soon as Amazon removed my IP from Spamhaus PBL (see answer below).

spam postfix email-server spf dkim

1 Answers

  1. Best Answer

    I think I found two possible reasons why mails are listed as spam.

    First, as someone previously suggested (and as I was already aware of), missing PTR for sending server could be main cause.

    Second, since this server is hosted in AWS cloud, and Amazon has worked with Spamhaus to add all their IP ranges to PBL by default, it could also be the reason... From what I know, PBL has certain weight in deciding if email will be marked as spam or not. Also, Amazon has blocked requests for removal of their IP's from Spamhaus PBL list directly - requests have to go through Amazon. Luckily, they offer a way to remove Elastic IP from this list, and to setup a PTR record, while you're at it.

    So I'll see what happens after this process is complete.

    UPDATE: Amazon added correct PTR record, and it didn't resolve the problem. However, after they removed IP from Spamhaus PBL, mails stopped being sent to spam. Meanwhile, many SMTP servers stopped accepting mails from my SMTP because of this PBL list, which was also resolved when PBL record was removed.

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