Certificates on mail protocols -> additional domains

[ufficiotecnico]

Good morning

I present to you a situation I have on a server.

To simplify, we have two domains: lino.cloud and mondo.it

The server is configured as the main domain lino.cloud, which also has the certificates generated by letsencrypt while the additional domain has a certificate purchased from ssls.com and correctly loaded as you can see:

However, when I configure the e-mail on client indicating as host mondo.it in IMAPS or POP3S an error appears: (hostname in certificate didn’t match <mondo.it>! = <Box.lino.cloud> OR <box.lino. cloud> OR <lino.cloud> OR <mail.lino.cloud> OR <www.lino.cloud>)

I checked “System -> External DNS” of the main domain: :

While the additional domain:

As you can see, the MX record of mondo.it is pointed to box.lino.cloud

So from “System -> Custom DNS” it is possible to change the MX record of mondo.it and consequently when I configure the Mondo.it email client as an IMAPS or POP3S host, does it take the mondo.it certificate?

By inserting the trailing period and the IP address of itself, this replaces the MX record that runs on box.lino.cloud?

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Another question: clicking on “Repalce Certificate” of a domain of any level, is the entire certificate of the entire domain replaced?

Let me explain: ssls.com sells the “Positive SSL” basic package for approx. 5 € / year and includes the basic domino + www, for example lino.cloud and www.lino.cloud
If I substitute this certificate for the one I currently have, which also includes other third levels eg. mail.lino.cloud, box.lino.cloud in your opinion what could happen?

In any case, do I save this folder / home / user-data / ssl everything related to the certificate is saved? Could I replace it if there was any problem or is some special operation necessary?

[alento]

With MiaB your mail protocols will ALWAYS use the box’s default hostname.

MiaB does not follow the same pattern that cPanel or DirectAdmin servers use.

The server hostname is the server hostname. There is no ‘whitelisting’ available.

[ufficiotecnico]

Thanks alento;

Regarding the second question; what kind of certificate should I buy (https://www.ssls.com) unless you recommend something else? (exclude letsencrypt)

“PositiveSSL” -> with lino.cloud + www.lino.cloud

or

“PositiveSSL Wildcard” with infinite subdomains?

And can you tell me this too, always in relation to our configuration you see above?

“In any case, do I save this folder /home/user-data/ssl everything related to the certificate is saved? Could I replace it if there was any problem or is some special operation necessary?”