RFC 6186 SRV "template" records

Nothing on this post has been tested. Anything reported, until now, is only a mind exercise
I don’t know which clients supports/use configuration via RFC 6186 SRV records

I’m getting into a… mailserver. With some wish for autosetup clients. For email and calendar/addressbook sync.

Goal: WebTop, iOS, Android, more clients in sync.

One step is using AutoMX/AutoConfigure/AutoDiscover. Separate thread for that.
Other step might be RFC 6186 records on DNS server.

The one published on internet for the domain, but who knows, maybe in the future even the on LAN.
Anyway: feel free to check SRV record statements here
https://datatracker.ietf.org/doc/html/rfc6186

Feel free to replace yourhost.yourdomain.tld with your proper hostname, before taking the chance on your DNS.

_submission._tcp     SRV 0 1 587 yourhost.yourdomain.tld.
_imaps._tcp    SRV 0 1 993 yourhost.yourdomain.tld.
_pop3s._tcp    SRV 0 1 995 yourhost.yourdomain.tld.
_caldavs._tcp    SRV 0 1 443 yourhost.yourdomain.tld.
_calddavs._tcp    SRV 0 1 443 yourhost.yourdomain.tld.

According to the paper for _submission

submission: Identifies an MSA using [RFC4409]. Note that this covers connections both with and without Transport Layer Security (TLS) [RFC5246] as defined for SMTP in [RFC3207].

So your server should allow TLS with login on port 587, not only on port 465.

2 Likes

I’d be curious to know which clients use the SRV records, rather than (or in addition to) the autoconfig/autodiscover/mobileconfig. Kind of frustrating that the client authors can’t seem to get it together here.

One thing that the SRV records don’t do, but the other methods could (though automx doesn’t implement this at all reliably), is provide a display name for a given address. But I’d gladly sacrifice that for a single, widely-supported standard. I won’t hold my breath waiting, though.

Someone already asked for that on StackOverflow.

Not an overwhelming list of “positive” answers.

I was about to post that link myself. As yet, my Google-fu has failed to come up with a single client that actually uses these records. Doesn’t mean it doesn’t exist, of course, but it doesn’t seem to be something people are talking about.

My google-fu stumbled upon this.

I can relate why he/she 's suggesting to associate that with DNSSEC. Still another “not that spread” standard…

Edit. found one!
https://www.horde.org/apps/imp/docs/RFCS

That bug against Thunderbird has been open for 16 years, predating the RFC by 6 years, though even with recent activity it doesn’t seem to have any real traction. And while I love Horde, I’d really be curious how, and to what benefit, it implements RFC6186. It seems of minimal benefit for something that’s running server-side anyway.

The author works for Apple, but Apple doesn’t implement it. Curious.

Not all workers can tell the boss “we should do that” :wink:

Maybe both of you smart people can point me in the right direction as well. I’m new to the auto-discover feature and the formatting/specs are something I’m still learning. So far I love using Sogo/ActiveSync primarily using Outlook applications (both Windows/Android) and now I have to manually populate the settings in Outlook beyond a username/password autodiscover as desired. From what I am reading so far I have maybe 2 - 3 options available to me:

SRV DNS records as described by @pike
Static XML file
AutoMX

The static XML approach @danb35 has documented for us. I can get to the full deployment/cert & DNS entries but the formatting of the actual 2 XML files are specified for IMAP/SMTP. Here is where I get stuck not knowing how to format the MXL file for ActiveSync & how to properly pipe it into my SOGo setup. Is there a central place/resource you could direct me towards that helped you learn/understand the needed formatting?

Edit -

Summary

This might be the wrong post & sorry if it is. It looks like I would use the SRV record to point to something like autoconfig.example.com and then modify the XML file with something like:

-<Action>

-<Settings>

-<Server>

<Type>MobileSync</Type>

<Url>https://mail.example.com/Microsoft-Server-ActiveSync</Url>

<Name>https://mail.example.com/Microsoft-Server-ActiveSync</Name>

</Server>

</Settings>

</Action>

Are you asking about the formatting of the XML to specify the mail servers? It’s exactly as shown on the wiki page you cite–just replace the FQDNs as appropriate, and change the Display Name to whatever you like

If you’re asking about specifying anything else in the XML, the only documentation I’m aware of is linked near the top of that wiki page, in the paragraph that starts, “This guide is heavily based on…”.

https://wiki.nethserver.org/doku.php?id=email_autoconfiguration
Wiki referred by @danb35
And this

is the right topic about autodiscover/autoconfigure…

Yes & no. Following along the static XML guide with the sample config the setup looks to be for IMAP/SMTP. With SOGo, we use ActiveSync to push everything & trying to define/implement those settings into the XML file is what I am after. The closest thing I have come across for reccomended Activesync XML settings comes from Zoho. Do you know of a central place akin to a Man Page for Autodiscover?

I’m sure I am not asking this correctly but this is akin to trying to use a new command and what parameters are available with the command by typing something like --help at the end of it.

UPDATE - here it is just like you said. TY.