http://www.tldp.org/HOWTO/DNS-HOWTO.html
http://www.acmebw.com/askmrdns/archive.php?question=7
http://directory.google.com/Top/Computers/Internet/Protocols/DNS/
http://194.96.20.67/langh/uploads/media/bind9.pdf
http://www.zoneedit.com/
www.dnsreport.com/tools/dnsreport.ch
