Sometimes XMPP-Messages get lost without notice, sometimes the server on the sending site sends a nice notification (“could not deliver blah…”). Problem exists in both directions.
Servers involved: jabber.ccc.de and talk.google.com
Also, messages tend to need a very long time to arrive, if you just logged on (quick test shows 58s from ccc to google).
And more weird things happening: contacts seem to go offline even if they are, in fact, online. Messages get through flawless, though.
I should write something to do some automated testing, preferrably involving other Jabber servers as well… If I just weren’t so lazy…