DNS Infrastructure Basics

Last Updated: 15 March 2013

This area of the site will be dedicated to introductory material related to the Domain Name System (DNS) technical aspects.

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Country Code Top Level Domains (ccTLD)
In a web address, a top-level domain (TLD) is the series of letters that come after the rightmost dot. (In icann.org, the TLD is .org.) There are generic TLDs, such as .com, .net, and .info; and there are country code TLDs, such as .uk (United Kingdom) and .jp (Japan). Learn more about ccTLDs at their homepage: http://ccnso.icann.org/.

Documents Date Format File Size (Duration)
What is a ccTLD? (Podcast) 1 Mar 2010 MP3 14 MB (11:42)
What is a ccTLD? (Podcast Transcript) 1 Mar 2010 PDF 33 KB


DNS-Computer Emergency Response Team
In order to work, the Internet relies heavily on the Domain Name System. Should ICANN create a security coordination center, for timely response to emergencies and attacks on the DNS?

Documents Date Format File Size (Duration)
Global DNS-CERT Business Case:  Improving the Security, Stability, and Resiliency of the DNS 12 Feb 2010 PDF 600 KB
Consultation on Security Strategic Initiatives (Briefing) 24 Jun 2010 MP3 25 MB (60:00)
How Domain Name Servers Work: Introduction (Article) N/A Webpage


Internet Protocols (IPv4 and IPv6)
Internet protocol addresses (IP) allow computers on the Internet to find one another. Here, you can learn what IPv4 and IPv6 are; when the Internet might run out of IPv4 addresses; and how moving to IPv6 could affect registries, registrars, businesses, and individuals.

Documents Date Format File Size (Duration)
What Does IPv6 Mean? (Podcast) 29 Apr 2010 MP3 26 MB (26:42)
What Does IPv6 Mean? (Podcast Transcript) 29 Apr 2010 PDF 65 KB


Redirection and Wildcarding
When you enter a domain name in your web browser and the domain doesn't really exist, you should get an error message. But sometimes you receive "synthesized DNS responses" – an ad, a search engine, a suggestion of what you meant. These "wildcard" responses could actually harm the Internet.

Documents Date Format File Size (Duration)
Redirection and Wildcarding (Podcast) 25 Nov 2009 MP3 20 MB (14:26)
Redirection and Wildcarding (Podcast Transcript) 25 Nov 2009 PDF 32 KB