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An option to use actual reverse DNS resolution as HELO for outbound email.

cPanel Phil Stark shared this idea 10 years ago
In Progress

As an administrator, I would like to have an option for cPanel to automatically find and use the reverse DNS resolution of the sending IP address for outbound email.


This would resolve the administrative headaches of having to manage /etc/mailhelo and /etc/mailips manually as well as issues with getting blacklisted on RBLs for using multiple or mismatched HELOs when these files are getting managed automatically.


If the HELO always matches what is in the actual PTR record for the IP, all is well.

Replies (7)

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this is such a vital option that anyone who is not using it is totally oblivious.


if you have each domain sending mail from it's own IP address (and you should) and you have serveral shared IPs (which have several domains sending mail from it) you could get listed on blacklists for having different helo names from the same IP

(actually happened)


since using the script we have had no problems with multiple domains on same IP

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this script started generating some invalid values in /etc/rdns and /etc/mailhelo

it would be nice to have it published in CPanel and be supported.

For those who do not understand:

when sending mails from cpanel, the mails get sent:


  1. from server's main IP (bad idea as ALL mail will be sent from the same ip and reputation can suffer)
  2. or each account's IP address (ideal as clients can buy dedicated IPs and have their own mailing
    reputation, also easier to identify spammers and prevent blacklisting)

however for option 2 cpanel uses the main server address or the domain name that is sending the mail as MAILHELO.

mailhelo is part of the email header.


In the case that you have more than one shared IP (also common practice, to distribute not more than 20-30 accounts per shared IP), or simply have more than one domain in an account on a dedicated IP address, then these accounts will put their own domainname as mailhelo and will trigger some blacklist (invalid RFC validation)


the solution is to use the proper RDNS value in the mailhelo, per RFC specification, this will also validate the email and better inbox deliver. even if we are sending mail from mimimail.com the mailhelo should be the sending IPs' reverse dns value


please support this implementation

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Option 2 that you mention is not working as you explained.

If we choose that emails will be sent from dedicated ip HELO is always using servers shared hostname and causing issues with Hotmail etc.


We have contacted cPanel many times on this issue but no solution yet.

So when a shared ip is blacklisted and customer buy's dedicated ip they can again send email, but get issues to hotmail etc.


This is a pain and headache all the time!

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Hey all! Got a question from dev to pass on to you: How would you all feel if we implement this request and make it the default setting going forward (either on new installs or with the upgrade to cPanel & WHM Version 80)? What concerns do you have with us implementing this feature? what use-cases do you have that might prevent this feature from working the way we intend?

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I agree, because servers check reverse dns + helo hostname / banner by default. I need to use /etc/mailhelo manually to use several IPs on the same server. But need a way to "clear dns cache" (or reload), due to new servers while installing.

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I am using the cpanel provided script for updating the mailhelo files from the reverse records

I would prefer having a built-in solution to have HELO automatically set correctly to the reverse value

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It is very important thing! For now all my customers are asking me why they have errors in cPanel e-mail deliveribility check. This check it WRONG, becouse I have correct revDNS entries. But I cannot edit manually /etc/mailhello every time ...


Mail helo should be taken from real revDNS entry.

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Any update on release time

82 is out and no word on when this will be available.

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Guys, you just increased the prices and could hire 100's of developers and make this feature within a couple of days.Please get it prioritized and make it happen!

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