[Standards] Call for Experience: XEP-0368: SRV records for XMPP over TLS

Dave Cridland dave at cridland.net
Thu Feb 13 09:31:26 UTC 2020

On Tue, 11 Feb 2020 at 16:30, Jonas Schäfer <jonas at wielicki.name> wrote:

> The XEP Editor would like to Call for Experience with XEP-0368 before
> presenting it to the Council for advancing it to Final status.
> During the Call for Experience, please answer the following questions:
> 1. What software has XEP-0368 implemented? Please note that the
> protocol must be implemented in at least two separate codebases (at
> least one of which must be free or open-source software) in order to
> advance from Draft to Final.
Metre (MIT-licensed) has supported the majority of the specification over
S2S for some time, but it does not follow the SHOULD of using ALPN - §3
point 7.

Openfire (Apache-licensed) has supported listening for Direct TLS on both
C2S and S2S for... ever? I believe it supports the SRV records now but I'll
leave it to Guus to explain that.

> 2. Have developers experienced any problems with the protocol as
> defined in XEP-0368? If so, please describe the problems and, if
> possible, suggested solutions.
The SHOULD for ALPN does not seem to be widely implemented. I suspect that
ALPN is more relevant for C2S than S2S in any case, but I think it's
worthwhile to consider dropping this to a MAY given this is both rarely
implemented and very rarely deployed.

> 3. Is the text of XEP-0368 clear and unambiguous? Are more examples
> needed? Is the conformance language (MAY/SHOULD/MUST) appropriate?
> Have developers found the text confusing at all? Please describe any
> suggestions you have for improving the text.
Aside from ALPN, as noted above, there is the question of mixing the
xmpps/xmpp variants.

I'm fine with this personally (Metre implements as specified), but I
understand that some libraries find this difficult.

I note that RFC 6186 uses a slightly different "mix", by selecting the
protocol based on priority only (and then performing weight selection only
within a protocol).

Broadly, I am in favour of relaxing the mixing definition - I believe that
initiators which favour direct TLS are fine (and even sensible), and
initiators which choose to select both are entirely reasonable as well.

> If you have any comments about advancing XEP-0368 from Draft to Final,
> please provide them by the close of business on 2020-02-25. After the
> Call for Experience, this XEP might undergo revisions to address
> feedback received, after which it will be presented to the XMPP
> Council for voting to a status of Final.
> You can review the specification here:
> https://xmpp.org/extensions/xep-0368.html
> Please send all feedback to the standards at xmpp.org discussion list.
> _______________________________________________
> Standards mailing list
> Info: https://mail.jabber.org/mailman/listinfo/standards
> Unsubscribe: Standards-unsubscribe at xmpp.org
> _______________________________________________
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.jabber.org/pipermail/standards/attachments/20200213/3b1193b7/attachment.html>

More information about the Standards mailing list