Domain Name Systems (DNS)

Among the activities of the Inter-American Telecommunication Commission (CITEL), which is the unit in charge of telecommunications inside the Organization of the American States (OAS), various communication technology topics are being dealt with on a permanent basis.

For example, the previous report on domain names focusing on how complex it is to administer them and on conflict resolution in the Americas is noteworthy.  The present document proceeds along the same line of work.  

The Domain Name System (DNS) is the system for resolving Internet addresses.  For the purpose of introducing and explaining the subject simply, we can say that, when a web address, also known as the URL (Uniform Resource Locator), is introduced into a computer (for example, www.xxzz.com.xx), it actually involves a mnemonic technique to make it easy to remember the address.  The truth is that the name corresponds to what is called the “IP Address” (for example, 200.123.43.112) and this address is stored in directories that have millions of addresses and are distributed throughout the world.  Access to these directories can generally be gained by an inverse hierarchy methodology.  The root server or the top-level server is the last one to be consulted.  These directories also have an inverse resolution system; when the system is given an IP address, it will find the corresponding domain name.  The location of an address is indispensable to find a site or web page or to send a message to a given address. The DNS system consists of three basic subsystems:

• The DNS data, called resource records, which include billions of registers distributed throughout millions of files called “zones.”

• The name servers, where these data are filed.

• Finally, the Internet protocols for handling information between servers.

The customary path for a URL search on Internet may, for example, be as follows:

Where:

• ISP is the Internet service access provider

• Internet is the network

• A) The serve where the page is housed or the service that is being searched.

• B) The NIC server or the country-zone point

• C) One of the root servers

A –       If the ISP has the IP address of the page or service that is requested in its directory, it will route the requested communication directly.

B –       If the ISP did not have this information, it could consult the NIC server of the country or another zone server.

C –     As a last resort, one of the root servers or one of their replicas is used [Replica: A server with characteristics that are identical to those of the root server and that performs the same functions, in addition to redundancy capacity.].

About root servers:

Root servers are named after one of the letters of the alphabet ranging, until now, from “A” to “M”.  These root servers or root directories are distributed as follows:  10 inside the United States, 1 in Japan, and 2 in Europe, which in turn have their replicas inside Europe and Asia.

With the advent of a new technology called Anycast, replicas of root servers can be generated.  This has made it possible for a number of these to be generated outside the United States, which is for the benefit of connectivity and also security.  The possibility of keeping the directories distributed in a larger number of servers makes the network safer against any type of attack or operational difficulty.

The root server that has the highest number of mirrors is “F”, which is operated by Internet Systems Consortium, Inc. The table of how they are distributed and who their respective operators are is provided below.

Where more than one geographical location has appeared, it means that Anycast replicas of the root server have been generated.

As part of this policy of creating Anycast, LACNIC (IP Address Register for Latin America and the Caribbean) is developing a program to install servers on the basis of this technology in the region.  This will optimize the search time of the domains and, as we indicated earlier, will enhance network security.

This is a simplified summary of a topic of the utmost importance in the Web, Internet, and its operators.

Oscar Messano
Rapporteur Study Question I:
Internet Domain Name Signatures
Working Group on Advanced Network Technologies and Services