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Host with "no rDNS" problem

Discussion in 'E-mail Discussion' started by webmasteryoda, May 5, 2017.

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  1. webmasteryoda

    webmasteryoda Well-Known Member

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    Hello

    I have some issues with my email server. Its not sending emails to some hosts (mostly Microsoft servers).

    Firstly, I must say that I configured my server few days ago. And its properly configured.

    When I check mail-tester.com, my results are 8.8/10.
    It says I am properly authenticated. SPF, DKIM, DMARC - all ok!

    It also says that my rDNS is fine. But...

    Spam Assassin thinks I can improve. Here is what Spam Assassin says:
    -1.274 RDNS_NONE Delivered to internal network by a host with no rDNS
    This may be a false-positive, please check the reverse DNS test below to confirm or not this issue

    But, as I already said, my rDNS resolves to IP address from which I am sending email.
    So, why are some servers seeing my rDNS as invalid.

    I must say that I am using additional IP address, which is HELOing to my hostname (which is NOT a domain name of the sender).

    Any clues?
     
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  2. cPanelMichael

    cPanelMichael Technical Support Community Manager
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    Hello,

    The following document is a good place to start if you want to ensure your server is following the best practices for successful delivery to remote mail servers:

    How to Keep your Email out of the Spam Folder - cPanel Knowledge Base - cPanel Documentation

    If you have configured Exim to use a different IP address, the PTR record of that IP address should use the hostname of your server. Do you receive a specific bounce message from the servers that are rejecting your messages?

    Thank you.
     
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  3. webmasteryoda

    webmasteryoda Well-Known Member

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    Sure. Here is delivery report from one of these messages:
    SMTP error from remote mail server after RCPT TO:<xxxxxx.yyyyyyyyy@zzzzzz.yy>: 451 bad reverse dns

    But it is not a bad reverse dns. Here is my servers setup:

    111.111.111.111 (main servers IP) - hostname.server.com
    222.222.222.222 (dedicated IP for a sending domain) - sendersdomain.com

    rDNS for both IPs = hostname.server.com

    /etc/mailhelo:
    sendersdomain.com: hostname.server.com
    *: hostname.server.com

    /etc/mailips
    sendersdomain.com: 222.222.222.222
    *: 111.111.111.111

    Is this preferable configuration?
     
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  4. cPanelMichael

    cPanelMichael Technical Support Community Manager
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    Hello,

    Here's a quote from our documentation regarding the manual changes to those files:

    As far as your configuration:

    In the /etc/mailhelo file, you can leave "*: hostname.server.com" as the sole entry in this file. This information is documented at:

    How to Configure the Exim Outgoing IP Address - cPanel Knowledge Base - cPanel Documentation

    How long ago was the RDNS entry updated? Could it be an issue where the DNS change has yet to propagate?

    Thank you.
     
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  5. webmasteryoda

    webmasteryoda Well-Known Member

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    Yes, I followed that article when configuring mail server.

    RDNS was changed 2 days ago. So, it should be fine?

    Is it possible to use 2 different HELOs on the same server?
    (both IP addresses to have different reverse DNS and configured on the same server?)
     
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  6. cPanelMichael

    cPanelMichael Technical Support Community Manager
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    Yes, that shouldn't prevent email delivery. The following thread also offers some tips that may help address the issue you are facing:

    Major Issues with Email

    Thank you.
     
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  7. webmasteryoda

    webmasteryoda Well-Known Member

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    Hello

    Its been awhile since I posted this. I was researching the problem, and I`ve read all of the articles, but the problem stays.

    I didnt solved it.

    But here`s an interesting detail.

    When I do:
    dig +short -x @localhost xxx.xx.xx.xxx (my main servers IP)

    I get nothing!
    My own server cant find RDNS ???

    How can it be?
     
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  8. cPanelMichael

    cPanelMichael Technical Support Community Manager
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    Hello,

    Feel free to open a support ticket using the link in my signature if you'd like us to take a closer look.

    Thank you.
     
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