Whenever I have to configure an newly-installed email client I remember one of the long-running topics on my task-list was to setup autoconfiguration for email clients. It’s one of those things one does occasionally (with one’s own domain) so it always seems quicker to set up manually and “get back to it another time”.
The use dates back to fairly early in Thunderbird, and quite a number of mail clients now utilise the same autoconf method.
As it turns out the original author/developer started the IETF RFC publishing process a couple ago as draft-bucksch-autoconfig.
The current mail-client autoconf service is documented well by Mailbox.org. It includes the most information in one place.
The mailbox.org document references Ben Bucksh’s authoritative Thunderbird autoconfig documentation (which, unsurprisingly, makes up the majority of his draft RFC).
It appears that Microsoft has used a different DNS host (and/or SRV record), but the same configuration file, which the mailbox.org document covers should you wish to include Microsoft mail clients.
Basically:
* create a website autoconfig.${DOMAIN}
* get a TLS certificate (if preferred)
* create an xml config file, config-v1.1.xml to be saved in the website and referenced as, eg, https://autoconfig.example.com/mail/config-v1.1.xml
* Add CNAME/SRV records for Microsoft clients, as below.
* test by setting up a new account on an existing or new email client, and use the wizard/autoconfiguration.
DNS records for Microsoft clients:
CNAME:
autodiscover CNAME example.org.
SRV:
_autodiscover._tcp SRV 0 0 443 example.org.
A further step would be to configure calendar clients, which appear to reference RFC6764 as a means for autoconfigure; further investigation for another day!