Domain Naming System, DNS Zones, Records, NameSpace

Article Index

DNS RECORDS

DNS records or Zone files are used for mapping URLs to an IPs. Located on servers called the DNS servers, these records are typically the connection of your website with the outside world. Requests for your website are forwarded to your DNS servers and then get pointed to the Web Servers that serve the website or to Email servers that handle the incoming email.

DNS Records Types:-

ThisList of DNS record typesprovides an overview of types ofresource records(database records) stored in thezone filesof theDomain Name System(DNS). The DNS implements a distributed, hierarchical, and redundant database for information associated with Internetdomain namesand addresses. In these domain servers, different record types are used for different purposes.

The below DNS records are mostly used in all DNS Configurations. Now we will see each one with examples.

DNS RESOLVERS

DNS works in a client/server fashion. DNS servers respond to requests from DNS clients calledresolvers.ISPsand other organizations set up local DNS resolvers as well as servers. Most DNS servers also act as resolvers, routing requests up the tree to higher-level DNS servers, and also delegating requests to other servers. DNS servers eventually return the requested mapping (either address-to-name or name-to-address) to the resolver.

Name Space

The domain name space consists of atreeof domain names. Each node or leaf in the tree has zero or moreresource records, which hold information associated with the domain name. The tree sub-divides intozonesbeginning at theroot zone. ADNS zonemay consist of only one domain, or may comprise many domains and sub-domains, depending on the administrative authority delegated to the manager.

DNS is the name service provided by the Internet for TCP/IPnetworks. DNS is broken up intodomains, a logical organization of computers that exist in a largernetwork. The domains exist at different levels and connect in ahierarchythat resembles the root structure of a tree.

 

DOMAIN NAME REGISTRATION

The right to use a domain name is delegated bydomain name registrarswhich are accredited by theInternet Corporation for Assigned Names and Numbers (ICANN), the organization charged with overseeing the name and number systems of the Internet. In addition to ICANN, each top-level domain (TLD) is maintained and serviced technically by an administrative organization, operating a registry. ICANNpublishes the complete list of TLD registries and domain name registrars. Registrant information associated with domain names is maintained in an online database accessible with theWHOISservice. For most of the more than 240country code top-level domains(ccTLDs), the domain registries maintain the WHOIS (Registrant, name servers, expiration dates, etc.)

DNS ZONE

Zones are name space area represented by a FQDN in other words information about records of the resource within your DNS domain in stored in a zone file and this zone file exists on the hard drive of one of your name space server. General there is two types: - (1) Forward lookup zone (2) Reverse lookup zone.

Zone categories

Zone in divided in three categories

  1. Primary Zone: - A primary zone server is the master server of that zone. It includes all the records.
  2. Secondary Zone: -This are called backup zone server and contains the copiers of master sever records.
  3. Stub Zone: -Stub zone one mini zone that contains few records that host for master zone. It is similar to the secondary zone but it contains only following records.
  • SOA (Start Of Authority) Record
  • NS (Name Space) Record
  • Host (A) Records

DNS DELEGATIOn

It is process of Transferring authority a zone from one server to another server.

Likewise, an organization administering a domain can divide it into sub domains. Each of those sub domains can bedelegatedto other organizations. This means that an organization becomes responsible for maintaining all the data in that sub domain. It can freely change the data, and even divide up its sub domain into more sub domains and delegate those. Theparent domain retains only pointers to sources of the sub domain's data so that it can refer queries there.