How to customize Exim HELO/EHLO without changing system hostname?

[servtelecom]

Hi everyone,

I am looking for the proper way to customize the Exim HELO/EHLO identity in HestiaCP to match my PTR (Reverse DNS) record, while keeping a different system hostname for the panel access.

I currently have my system hostname set to cpanel.domain.com for panel management, but my mail server needs to identify as mail.domain.com to pass spam filters and maintain proper reputation (matching the IP’s PTR record).

I have tried modifying the exim4.conf.template file to force a custom helo_data and smtp_active_hostname, but HestiaCP’s internal logic keeps reverting these changes or ignoring the custom configuration.

Is there a “Hestia-native” way to handle this separation of identities? Any guidance or recommended workflow to achieve this without fighting against the panel’s configuration engine would be greatly appreciated.

Thanks in advance!

[sahsanu]

Hi,

@servtelecom

I have tried modifying the exim4.conf.template file to force a custom helo_data and smtp_active_hostname, but HestiaCP’s internal logic keeps reverting these changes or ignoring the custom configuration.

That should work. Did you take a look to this post?

Mail sent with the wrong domain

That’s a different “problem”. Is your server using the right hostname? Anyway, you can force Exim to use the hostname you want. First, backup exim conf just in case… Check what are the directives using lookup dnsdb to get the primary_hostname: grep '${lookup dnsdb{>: defer_never,ptr=$.*}{${listextract{1}{$value}}}{$primary_hostname}}' /etc/exim4/exim4.conf.template You should see 3 of them, one smtp_active_hostname and two helo_data. Search them in exim conf file /etc/exim4/exim4.conf.tem…

[servtelecom]

But can this be done from the HestiaCP panel itself? Edit Exim4 from there? It would be very useful to be able to customize the name from the Exim4 service settings, so I could have one name for the panel and another for Exim4 to comply with Reversio IP rules…

[sahsanu]

@servtelecom

But can this be done from the HestiaCP panel itself?

Yes and no. There is no specific field in Hestia to tell Exim to use x hostname but you can edit Exim conf from Hestia.

[servtelecom]

Perfect, I’ll apply the solution you suggested, but as a suggestion… it would be good if the Exim4 certificate name could be customized and not be the hostname. That way, the certificate could be separated from the hostname so that when accessing https://panel.domain.com, it could be used perfectly without interfering with the Exim4 certificate name (e.g., servmail.domain.com). Thanks for your support!