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Networking: DNS

Elaborate on the following about DNS:
DNS is both a telephone "White Pages" and a "Yellow Pages."
The DNS namespace
The hierarchy of DNS servers and how they work as a team to resolve DNS queries.

Concerning IP address assignment:
Describe the four steps in the DHCP address assignment process.
What is the 80/20 rule with respect to DHCP?
Which IP addresses should be assigned manually?
Concerning subnetting:
What are some advantages of subnetting?
Describe address classes.
How are default subnet masks determined?
What are two methods of conserving IP addresses? Explain these methods.

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1) DNS is both a telephone "white pages" as well as "yellow pages"
Since DNS consist of hostname and there corresponding IP address, it is used for resolution of hostname into IP address. So, it can be called as "white pages".
DNS is also telephone "yellow pages", since its directory structure is an organized and hierarchal way i.e in a categorized manner, just like yellow pages contains categorized listing.
2)DNS Namespace: The DNS is (i) a distributed database implemented in a hierarchy of name servers and (ii) an application-layer protocol that allows hosts and name servers to communicate in order to provide the translation service. DNS is commonly employed by other application-layer protocols -- including HTTP, SMTP and FTP - to translate user-supplied host names to IP addresses
DNS is broken up into various domains which exist at different levels and are connected in a way resembles tree with a root structure. Every domain extends from the node above it. These domains begin at the top with the root-level domain. Under the root-level domain are the top-level domains, under those are the second-level domains(Authoritative domains), and on down into subdomains. This entire DNS domain structure is called the DNS namespace
3) DNS server's hierarchial structure consists of three classes of DNS servers-
i) Root DNS servers:
ii) Top level domain(TLD) DNS servers (e.g com DNS servers. Org DNS servers, edu servers)
iii) Authoritative DNS servers(e.g yahoo.com DNS server, amazon.com DNS server)
At the top of hierarchial structure are Root DNS servers, below them Top level domain DNS servers, below them are Authoritative DNS servers.
There is another class of DNS server which is local DNS server. Each ISP,university has a local DNS server. Whenever a host request for a hostname to IP resolution, this request goes to Local DNS server which forwards it to Root DNS server which returns address of TLD DNS server to local DNS server which again forward its request to TLD DNS server which returns address of Authoritative DNS server, the local DNS server then forward its request to Authoritative DNS server which returns its required IP address and it returns back this to host.

4)DHCP (Dynamic Host Configuration Protocol) is a protocol which is used to assign IP addresses to hosts dynamically. DHCP is a client server protocol. DHCP address assigning process consist of 4 steps which are as follows:
i)DHCP server discovery: A newly arriving host should first find a DHCP server for interacting. For this the host issues a DHCP discover message with a broadcast destination IP ...

Solution Summary

The solution discusses networking.

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