Main / Service Description / DNS: Domain Name System

DNS: Domain Name System

A DNS service resolves textual Internet domain names (e.g., cybermind-usa.net) into their numeric IP address counterparts. The sole reason that a need exists for DNS services is that IP addresses aren’t at all user friendly. For example, humans find it rather difficult to remember "198.70.62.16", but have no trouble remembering “cybermind-usa.net.” A DNS service makes the translation between the two.

In other words, DNS:

• maps a domain name to an IP address — What is the IP address of the host www.cybermind-usa.net? Answer: 64.33.121.19
• maps an IP address to a domain name "What is the domain name of the IP address 64.33.121.19?" Answer: www.cybermind-usa.net.
  

People working on computers around the globe maintain their specific portion of this database, and the data held in each portion of the database is made available to all computers and users on the Internet.

A few key points

Part of the TCP/IP protocol upon which the Internet is based relates to
network addressing.

• Every computer entity or node visible from the Internet requires a unique IP address.
• IP addresses are numeric and not at all user-friendly from a human perspective.
• Domain names are textual “aliases” for IP addresses.
• Domains are categories of domain names. The current system uses a set of top-level domains -.com, .net, .edu, .gov, etc. Plans are under way to expand this list.
• The “InterNIC” (www.internic.net) is the official organization managing the assignment of domain names.
• ARIN, the American Registry for Internet Numbers (www.arin.net) is a nonprofit organization managing the registration of IP addresses in certain geographical areas previously managed by the InterNIC (including North and South America).
  

Components of DNS

DNS has three components: the domain name space, name servers, and resolvers.

• The domain name space is simply the formal specification that defines how
  domain names will be structured and how the corresponding “resource records” will be handled.
• A name server is a server program that responds to requests for converting domain names into IP addresses and vice versa, by accessing its database of domain name-to-IP address mappings.
• A resolver is a program that makes the request to the name server for that
  conversion, at the user’s request.
  

For example, when you attempt to access the Web site www.cybermind-usa.net, part of the process of delivering it involves determining the IP address for “cybermind-usa.net.” This step is performed by a series of “name servers” on the Internet, whose job it is to respond to such queries.

“Forward” vs. “reverse” lookup

Requesting the corresponding IP address of a domain name is called “forward
lookup.” Requesting an IP address’ domain-name alias is called “reverse lookup.”
Name servers handle both types of requests. Resolvers make the requests on behalf of user applications.

DNS “name servers”

DNS name servers are engineered hierarchically and are distributed across the
Internet. The term “distributed” means that no central database contains all of the
Internet host name information. Instead, each organization connected to the Internet maintains its own database of name-to-address mappings, and runs a name server program that other client systems - resolvers - can query across the network. DNS defines the naming conventions used, as well as the protocol used by clients and name servers to communicate with each other to map host names into IP addresses.

cyberMIND provides DNS service through this nationwide DNS computer network
engineered to optimize DNS availability and performance. See cyberMIND's DNS for more information.

InterNIC servers
Part of this network of DNS servers is a series maintained by the InterNIC. These
servers contain “authoritative” copies of the databases that map top-level domain names to IP addresses. For each top-level domain - .com, .edu, .gov, etc. - there is a corresponding top-level-domain server.

Each top-level-domain (TLD) server contains a database of all InterNIC-registered
names within that domain, and their corresponding IP addresses. In fact, being
included in one of these databases is the practical result of being “InterNIC-registered.”

Root servers - there are nine of them - contain pointers to the TLD servers. When a root server receives a query, it directs it to the appropriate TLD server, which in turn directs the query to the appropriate owner-managed name server.

The root servers and top-level-domain servers are controlled by the InterNIC.
Authority for the other name servers is delegated to the owner of the domain as
recorded by the InterNIC when the domain name was registered.

All this is necessary to ensure that top-level domain names are unique. Just as no two physical locations can have the same mail address, no two network entities can have the same IP address/domain name. The InterNIC and ARIN ensure that top-level domain names, and corresponding IP addresses, are assigned to one — and only one — network entity.

cyberMIND’s DNS service

A DNS service manages the name-server function for a customer. To be accessible to the Internet, a network’s set of IP addresses must be made visible or “advertised” to the other Internet nodes. The InterNIC takes care of the top-level domain — e.g., cybermind-usa.net — with its system of root server and TLD servers, but the IP addresses within a domain are managed by and are formally the responsibility of the person or organization to whom the InterNIC has registered the domain.

Not all of the IP addresses within your network need be visible to the Internet - but those that will be visible must be maintained in a database, which itself is used by a name-server program to respond to queries from other Internet nodes for IP address/resource information within the domain. Maintaining this database, and providing your network with forward and backward lookup capabilities, is the job of cyberMIND’s DNS Services.

Primary vs. secondary DNS service

cyberMIND’s primary DNS service provides customers an authoritative source for DNS data. cyberMIND provides primary DNS for one top-level domain name (e.g.,
www.cybermind-usa.net) per order per customer. This includes managing the database that contains your IP addresses and handling the name-server function.

To obtain a Domain Name (.com, .biz, .net etc.) you may order your domain name through the cyberMIND eStore.

We provide the initial addition of the domain to the cyberMIND DNS, modifications to the record may be ordered through the cyberMIND eStore.

cyberMIND’s secondary DNS service provides customers a redundant source for DNS data when they are obtaining their primary DNS service from someone other than cyberMIND.

cyberMIND provides secondary DNS for up to 25 top-level domains.

If you use another primary DNS service provider

Primary DNS operators control the communication standards between primary DNS servers and cyberMIND’s secondary DNS servers. If you obtain Primary DNS services from a source other than cyberMIND, the primary DNS servers should contain records for the following domain names:

• ns.cybermind-usa.net
• ns2.cybermind-usa.net
  

cyberMIND recommends that primary DNS service operators authorize cyberMIND’s secondary DNS servers to obey the following communication standards:

cyberMIND’s role in registering domain names
If you are a cyberMIND Internet Dedicated Access customer and have ordered DNS, cyberMIND will assist you - at no charge - in registering your primary domain name with the InterNIC. You, however, will be responsible for paying the registration fee assessed by the InterNIC.
Other key points:

• You must provide Sprint with three alternative domain names (e.g., choice1.com, choice2.com, choice3.com), for use if your first choice is already claimed by someone else.
• You own your domain name, and it goes with you if you change ISPs.
• If you change TO Sprint from another ISP, Sprint will assist you in reregisteringyour domain with the InterNIC.
• If you change FROM Sprint to another ISP, responsibility for reregistering your domain rests solely with you.
  Making changes
  

Since you own your domain name, the InterNIC will accept changes only from you. This makes it your responsibility to keep InterNIC-registered data up to date.

Registered data includes customer contact, name-server names, and IP addresses. Customers are sometimes frustrated by the fact that cyberMIND cannot request InterNIC changes on their behalf. Unfortunately, this is an area outside cyberMIND’s control, and is unlikely to change. You must work with the InterNIC directly to keep information up to date.

If you are a cyberMIND secondary DNS customer, you must also keep cyberMIND informed of primary DNS name-server information changes.

For more information . . .

. . . on DNS: To learn more about DNS, including the technical detail required to write programs incorporating DNS capability, refer to the following Requests For
Comment:

• RFC1034 Domain Concepts and Facilities
• RFC1035 Domain Implementation and Specification
  

These are widely available for download from the Internet (search for “Domain Name System” using any Internet search engine (e.g., Yahoo!).

. . . on IP addressing: Use any Internet search engine to search for “TCP/IP” and select a topic.

. . . on the InterNIC: You can learn more about the InterNIC at http://rs.internic.net.

. . . on ARIN: You can learn more about The American Registry for Internet Numbers at http://www.arin.net.