Notes on now email clients check autodiscover domain settings.

autodiscover xml

    •    Autodiscover posts request to https://domain.com/Autodiscover/Autodiscover.xml.
where the domain.com is the email domain part of the email address used in account settings.
    •    Autodiscover posts request to https://autodiscover.domain.com/Autodiscover/Autodiscover.xml.
Autodiscover performs the following redirect check: GET http://autodiscover.domain.com/Autodiscover/Autodiscover.xml
where the domain.com is the email domain part of the email address used in account settings.
    •    Autodiscover uses DNS SRV lookup for _autodiscover._tcp.domain.com, if it exists, the "mail.domain.com" is returned.
where the email domain in _autodiscover._tcp.domain.com request is email domain name and the email domain name in mail.domain.com response is DNS name of the Kerio Connect server.
Autodiscover posts request to https://mail.domain.com/autodiscover/autodiscover.xml.

Configuration server at ISP
Given the email address "[email protected]", Thunderbird first checks http://autoconfig.example.com/mail/[email protected] and then http://example.com/.well-known/autoconfig/mail/config-v1.1.xml

Small company
If you are a small company, you can put the XML configuration file on your web server, at URL http://example.com/.well-known/autoconfig/mail/config-v1.1.xml. (This is not yet finalized and subject to change.)
http://autoconfig.example.com/mail/[email protected]