Is there a best way to provide email hosting such that email clients like Outlook and Mac Mail can automatically configure themselves given limited information (email + password)?
I'm guessing it might have to do with DNS entries - using [smtp|pop|imap].example.com, but I'd rather not guess if this is documented somewhere.
Mail clients which "discover" these things contain a list of probable values. The list will often contain specific values for certain commonly-used domains, and otherwise guess subdomains like
mail,imap,smtp, andpop, and then attempt the standard ports for each service. It basically repeatedly tries various settings until it finds a combination which allow it to connect. It is entirely client-side and there is no way at all to influence this from the server side (except providing sufficiently default services).That said, thunderbird and possibly some other clients support querying a subdomain (via http) for an XML configuration file. The subdomain is
autoconfig. For example, for[email protected], thunderbird will queryhttp://autoconfig.example.int/mail/config-v1.1.xml. The format of the file is described at the mozilla developer network and a description of exactly how to set it up is available there also.There was once talk of using
TXTandSRVrecords for this, but it's unclear if this has ever been implemented. Thunderbird in particular also has the ability to query a preinstalled XML config file and a config file athttps://live.mozillamessaging.com/autoconfig/<email-address-domain>.The latest versions of Thunderbird support something like this, but it's entirely a client-side trick. There are some semi-accepted ways to auto configure web browser proxies via DHCP, but I know of no way to do this for any common mail clients.
If you find a more satisfactory answer, it will be very email client specific. So you might try searching (or re-asking) for the specific mail client(s) you need to support.