Outlook and a number of other email clients now feature autodiscovery of mail server settings and it bugs me that I don't have this set up for our domains, but I'm not sure how to do it and a quick google hasn't turned up anything. I presume it's done with some kind of SRV record in DNS - is this correct and if so what's the correct format?
I am sorry I might be late to the party here. If you are still looking for a solution, I spent a weekend figuring out how to provide Auto Configuration (autodiscover what Outlook 2010 calls it) for most popular email clients including iOS.
I wrote it all down in a blog post here: http://moens.ch/2012/05/31/providing-email-client-autoconfiguration-information/ (also available via archive.org)
Outlook 2010 actually does a combination of DNS lookup and XML config. It first does a SRV lookup for
_autodiscover._tcp.<yourdomain> and then does an xml POST request to your autodiscover url and expects an XML response. My post contains samples of the XML response and a link to the full autodiscover xml Response spec on MS technet.
In short: You can provide full autodiscover functionality to your users even without Exchange server.
RFC 6186 describes how to use SRV records for e-mail services. Summary:
- SRV records like
_submission._tcp SRV 0 1 587 mail.example.com.and
_imaps. (Last number is the port number.)
- When offering both IMAP and POP, use the first number to show which is preferred (lower is preferable).
I don't know which MUA's already implement this. Maybe KMail. Thunderbird not yet?