[Standards] NEW: XEP-0220 (Server Dialback)

Philipp Hancke fippo at goodadvice.pages.de
Tue Feb 19 19:17:42 UTC 2008

XMPP Extensions Editor wrote:
> Version 0.1 of XEP-0220 (Server Dialback) has been released.

I just noticed that you're omitting the text about reusing an existing
connection as mentioned in 3920/8.3 step 5 in what is now section 4.3.
Any particular reason for that?

The important implication from this reuse is that a verification request
may happen at (almost) any time on a inbound stream (as seen by the
authoritative server).

Steps 1 and 3 in the order of events are (therefore) optional and should
be marked as such.

and in section 4.4:
> The Authoritative Server determines whether the key was valid or
> invalid and informs the Receiving Server of its determination, where
> the <db:verify/> element SHOULD include the key sent by the Receiving
> Server:

This 'SHOULD' was neither in RFC 3920 nor in 3920bis-01. Why was it added?

And the last sentence before section 4.5:
> After receiving the verification from the Authoritative Server, the
> Receiving Server SHOULD terminate the stream between them and the
> underlying TCP connection.

Terminating that connection is a bad idea most of the time. That
connection may be used for establishing the
xmpp.example.com->example.org stream, which is usually needed quite soon
after the example.org->xmpp.example.com stream has been established.
Therefore I think that 'MAY' is more appropriate here.

A strategy that works well is to wait for the authoritative server to
close the connection (due to idleness) and reuse the connection as
described in section 4.1 if possible.

The piggybacking section only talks about piggybacking db:result.
3920bis-01 mentioned using it for db:verify also. Why was that removed?

I sometimes wonder why dialback works at all... ;-)


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