[jdev] Second-guessing dns for s2s

[JD Conley]

> >>Interesting solution but not exactly standard, and will only
> >>work between servers that are running Jive Messenger,
> >
> > True. However, the nice thing about the logic is that normal DNS is
> > tried first. We also recommend that users setup DNS for max
> > compatibility. Even so, the extra logic means that if normal DNS
isn't
> > or can't be setup, the service will still work if the other server
is
> > JM. So far, we don't see a reason that this couldn't be added as an
> > implementation recommendation attached to the RFC's.
> 
> This really sounds like a bad idea to me. This implies that in the
case of
> user
> error, for example a user who tries to connect to a service such as
> conference.uct.ac.za, a JM server will try to resolve and connect to
> uct.ac.za
> and then ac.za ? Just moving up the tree isn't a reasonable
assumption.

It seems like a reasonable, but obviously not 100% accurate, assumption
to me. Most installations run at least a conference server along with
their main server. With our server implementation you get conferencing,
pubsub, JEP-0065 Proxy, and a user directory installed and running by
default, all on the same host. If you want those to be available to the
outside world you have to setup quite a few DNS entries. As Matt
mentioned, it is often very difficult, or impossible, for administrators
to get DNS entries put in for all of the possible sub domains -- even
the root one.

> 
> Instead of 1 NXDOMAIN dns lookup result, you have either 3 failed
lookups,
> or
> perhaps worse, 2 failed connection attempts to resolvable addresses
which
> have
> no jabber servers running there, or perhaps completely unrelated
servers
> (in
> which case the failure gets even messier).

That doesn't seem so horrible to me. Personally, I'd rather have a more
simplified setup to increase adoption of cross domain XMPP/Jabber.

> 
> This is bad engineering i.t.o. creating undesirable impact on the
broader
> Internet.

What is the undesirable impact? Sure, there are a few more DNS lookups
and potentially more connections and some stream errors. That doesn't
seem like much of an impact. I don't see the harm in connecting to hosts
that do not provide service to the domain you need. This is flushed out
rather quickly in the S2S process.

-JD