I've found a series of excellent articles, quite unexpectedly, on ZDNet. All of them are from Christoph H. Hochstätter. He evidently knows his business when talking about [DNS servers](http://www.zdnet.de/sicherheits_analysen_zensurgesetz_provider_und_bka_mit_loechrigen_konzepten_story-39001544-41500342-1.htmDNS servers). I've updated my [article](dns-on-nonstandard-ports.html) according to his [list](http://www.zdnet.de/sicherheit_in_der_praxis_internetzensur_freie_dns_server_schuetzen_vor_falschem_verdacht_story-39001543-41500185-1.htmlist).