Asked By
chathu
100 points
N/A
Posted on - 05/03/2011
What is DNS? And what are the functions of the DNS?
Answered By
asiri
0 points
N/A
#88331
What is DNS and its functions?
It is not easy to remember the names of the IP addresses, which contain only the numbers. Therefore it is easy to remember alphanumeric names instead of remembering IP addresses. Therefore domain names have been assigned to each IP address. Example of Domain names is https://www.google.com/?gws_rd=ssl. The domain name system (DNS) is an Internet-wide distributed database that translates between domain names and IP addresses.
Answered By
AkashED
0 points
N/A
#88332
What is DNS and its functions?
Domain Name System is a hierarchical database system, which is used for resolve IP addresses from a Domain Name or host names.
It allows to give meaningful names to the hosts through URL system, instead of an IP Address which contains only numbers.
Answered By
chathu
100 points
N/A
#88333
What is DNS and its functions?
You have said it is a hierarchical system. Please tell me what the hierarchy of the DNS is and how it works.
Answered By
AkashED
0 points
N/A
#88334
What is DNS and its functions?
Domain Name System consist of Name servers which are arranged in a Hierarchical order. In the top of the hierarchy there is a root server. In the second level there are several Top Level Domain servers. Namely,
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Com
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Org
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Net
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Edu
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Gov
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Mil
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Arpa
In each top level domains there are several sub domains or siblings. This is the hierarchy of the Name Servers.
Answered By
asiri
0 points
N/A
#88336
What is DNS and its functions?
DNS Name Hierarchy
•DNS hierarchy can be represented by a tree.
•Root and top-level domains are administered by an Internet central name registration authority (ICANN).
•Below top-level domain, administration of name space is delegated to organizations.
•Each organization can delegate further.
Â
Top Level Domains
Â
•Three types of top-level domains:
–Organizational:3-character code indicates the function of the organization
•Used primarily within the US
•Examples: gov, mil, edu, org, com, net
Geographical:2-character country or region code
•Examples: us, va, jp, de
–Reverse domains:A special domain (in-addr.arpa) used for IP address-to-name mapping
–There are more than 200 top-level domains.
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com
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Commercial organizations
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edu
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Educational institutions
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gov
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Government institutions
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int
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International organizations
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mil
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U.S. military institutions
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net
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Networking organizations
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org
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Non-profit organizations
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Hiararchy of Name Servers
Â
•The resolution of the hierarchical name space is done by a hierarchy of name servers
•Each server is responsible (authoritative) for a contiguous portion of the DNS name space, called a zone.
•Zone is a part of the subtree
•DNS server answers queries about hosts in its zone
Root Name Servers (Root Servers)
•The root name servers know how to find the authoritative name servers for all top-level zones.
Â
Answered By
chathu
100 points
N/A
#88337
What is DNS and its functions?
But how does it resolve the IP address? What does happen when I type a URL?
Answered By
asiri
0 points
N/A
#88339
What is DNS and its functions?
1. User program issues a request for the IP address of a hostname.
2. Local resolver formulates a DNS query to the name server of the host.
3. Name server checks if it is authorized to answer the query.
a)If yes, it responds.
b)Otherwise, it will query other name servers, starting at the root tree.
4. When the name server has the answer it sends it to the resolver.
Answered By
chathu
100 points
N/A
#88341
What is DNS and its functions?
Thank you very much, Techyv and experts.
