June 04, 2012, 3:03 PM — As the operator of some of the core Internet name servers, including the DNS root, .com and .net, Verisign has a unique view into the challenges of transitioning to IPv6 and progress to date.
The purpose of a name server in the Domain Name System (DNS) is to translate the name of an Internet resource -- as examples, a website, a mail server or a mobile device -- to an Internet Protocol (IP) address. Domain names, such as www.VerisignInc.com, provide a textual, hierarchical identifier for an Internet resource in a higher-layer protocol such as HTTP. The corresponding IP address -- either the traditional 32-bit form in IP version 4 or the new 128-bit form in IP version 6 -- gives a routable, numeric identifier for the resource in lower-layer network communications.
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Thanks to the name-to-address translation provided by a DNS name server, when Verisign and other websites want to deliver content over IPv6, they don't need to use a different domain name (although they could do so). Rather, they can leave it to the Web browser, when running on an IPv6-enabled endpoint device, to look up an IPv6 address from the website's name server, and then to communicate with the website over IPv6. As a result, the grand upgrade currently underway from IPv4 to IPv6 largely impacts network communications, but not HTTP or other higher-layer protocols.
The simplicity of this higher-layer abstraction, of course, comes at a cost: The complexity of the implementations of services that translate between higher and lower layers of the stack.
DNS offers a good case study with its quadrupling of options due to IPv6. A name server hosts many "resource records," consisting of a domain name and associated information. Traditionally, requesters could only send DNS queries to look up resource records associated with a given domain name over the IPv4 protocol. Furthermore, if the associated information included an IP address, it could only be an IPv4 address (a so-called "A" record).