- sebastian@sebbe.eu:
When you enter your email address, it would be TRIVIAL to check the MX records for the domain and fill those in for the SMTP and IMAP servers, allowing users to more easily add (if needed) the domain prefix.
As pointed out here before, that approach would not generally work. Many organisations split services over different IP addresses, and the IMAP server need not bear any relationship to MX (inbound) or MTA (outbound).
Vendors use different types of autodiscover/autoconfig mechanisms. I have written a service that implements some of them:
https://rseichter.github.io/automx2/
It may be overkill for domains with a very small user base with purely static data, but for medium sized organisations upwards or for those who need to lookup email addresses from LDAP (matching an unrelated login name), automx2 provides a means of handing out config data to iOS/macOS Mail, some Outlook versions, Thunderbird, KMail, and more.
The documentation I pointed to also includes a description of some of the mechanisms and RFCs behind it, in case you are interested.
-Ralph