If you want to enable the auto-configuration in your e-mail clients in order to benefit from the auto-configuration assistants / auto-discovery offered by local programs. Then, you can do so by referring to an autodiscover/autoconfig XML file and other well-known URLs that are available on our web server, in your custom domain (e.g., mydomain.com) DNS records.
Set _autodiscover._tcp.mydomain.com as a SRV to mailfence.com: (for SMTP, IMAP, POP and Exchange ActiveSync protocol service discovery)
_autodiscover._tcp.mydomain.com. 600 IN SRV 0 0 443 mailfence.com.
Set _caldavs._tcp.mydomain.com as a SRV to mailfence.com: (for CalDAV protocol service discovery)
_caldavs._tcp.mydomain.com. 600 IN SRV 0 0 443 mailfence.com.
Set _carddavs._tcp.mydomain.com as a SRV to mailfence.com: (for CardDAV protocol service discovery)
_carddavs._tcp.mydomain.com. 600 IN SRV 0 0 443 mailfence.com.
Set autoconfig.mydomain.com as a CNAME to mailfence.com: (for SMTP, IMAP and POP protocol service discovery)
autoconfig.mydomain.com. 600 IN CNAME mailfence.com.
Note: Clients that cannot utilize DNS SRV records, will go for CNAME record. Please be aware that this will lead to a known SSL warning in some clients (e.g., Outlook).