How to use multiple email account on different domains with one mail server?
I have a droplet running a mail server with dovecot, postfix and mysql.
On this droplet I have multiple domains: example1.com, example2.com, and so on.
Postfix uses example1.com as the hostname so any email account firstname.lastname@example.org can authenticate to this server using a mail client and the SMTP/IMAP hostname: mail.example1.com
The problem is that email@example.com can't authenticate with the server using mail.example2.com.
What changes (probably DNS records) are required in order to allow each user to access the mailbox using the same domain name as the email account.
For example (using any mail client Outlook/Thunderbird/etc.):