autodiscover.xml & /mail/config-v1.1.xml for Outlook & Thunderbird email clients using postfixadmin
Postfixadmin setup https://www.exratione.com/2016/05/a-mailserver-on-ubuntu-16-04-postfix-dovecot-mysql/ Autoconfiguration of email clients: The Perl Script: https://github.com/virtualmin/virtualmin-gpl/blob/master/autoconfig.cgi The Apache config: https://serverfault.com/questions/829260/block-requests-from-bots-by-pattern-in-apache-with-mod-rewrite-mod-rewrite-not The STARTTLS problem https://www.virtualmin.com/node/52609 The
Outlook with email, calendar & contact sync
https://sourceforge.net/projects/outlookcaldavsynchronizer/ is an Outlook plugin that will sync with gmail or any other calDAV server. eg: https://www.cyrusimap.org/ (Email, contacts & calendar server)