automx2 (Re: What imap ssl/auth settings work best with MS Outlook?)

Ralph Seichter ralph at
Fri Apr 30 15:39:36 EEST 2021

* sebastian at

> 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:

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.


More information about the dovecot mailing list