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Flat Name Spaces                                  Hierarchical Name Space
                 The names were simple and easy to remember.           The authority to allocate and regulate name spaces in a
                                                                       hierarchical name space can be decentralised.
                 As it must be centrally regulated to minimise ambiguity   Each designated agent is given authority over the
                 and duplication, a flat name space cannot be employed   names in each division.
                 in a huge system like the internet.
                 A namespace's partitioning must be defined in such a way that it: Supports efficient name mapping; and ensures
                 autonomous control over name assignment.
                 Hierarchy of Name Servers

                 Name servers are computers that keep track of these changes and translate them between IP addresses and domain
                 addresses. The DNS and name servers work together to ensure that mail is sent to the correct person. They ensure
                 that you are directed to the correct location when you type in a web URL. They are in charge of appropriately routing
                 all Internet messages and traffic.

                 Ð ÐDNS servers are used to deliver information across a large number of computers.
                  ÐAs many domains as there are first-level nodes are created.
                 Ð
                 Ð ÐThe server is in charge of the zone and has some authority. The server creates a database called a zone file in which
                   all of the information for each node in the domain is stored.

                 Ð ÐA root server is one whose zone includes the entire tree. A root server, in most cases, does not keep any domain
                   information and instead delegates its power to other servers.

                 Ð ÐPrimary server keeps a file containing information about the zone for which it has the authority. It is in charge of
                   establishing, updating, and maintaining the zone file.

                 Ð ÐSecondary server receives all of a zone’s information from another server and stores it on its local disc. The zone
                   files are not created or updated on these servers.

                 Domain Resolution Process

                 A user’s browser must obtain the IP address and submit queries to the name servers. Domain name resolvers are
                 involved in this procedure.

                 Ð ÐRequesting Website Information
                    Let's go to a website by typing the domain name into the address bar of a web browser. The hostname, such as
                   www.cbse.nic.in, will be resolved by our computer. The IP address connected with the domain name will then be
                   looked up in our computer's DNS cache.

                 Ð ÐSend a message to the Recursive DNS Servers.
                    If the information isn’t in your computer’s local cache, it will go to a different server to get it. Similar like your PC,
                   recursive DNS servers save a local cache. Since many ISPs utilise the same recursive DNS servers, the common
                   domain name may already be cached. The inquiry will stop here if the domain has been cached, and the user will
                   see the webpage.

                 Ð ÐConsult the Trusted DNS Servers
                    If a recursive DNS server or servers can't find what they're looking for in their cache memory, they look elsewhere. The
                   query then moves up the authoritative DNS server chain. The search will go on until a nameserver for the domain is
                   found. These authoritative name servers are in charge of maintaining these records for their domain names.

                 Ð ÐAccess the DNS record
                    To find the IP address for www.cbse.nic.in, we'll look up the address record on the authoritative name server. The
                   record for www.web.com is accessed by a recursive DNS server from the authoritative name servers. The record is
                   then saved in its local cache.
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