difference between dns & dhcp with detail &what is use of thees?

Answer 1

DNS is Domain Name Service. It translates URLs into IP addresses. In other words, it means you can get to Yahoo by typing www.yahoo.com into your browser instead of a string of numbers. On the Internet,. DNS is taken care of by a network of HUGE connected servers that do nothing but maintain address information. When you configure a computer to connect to the Internet, one piece of information you need to give it is what DNS server it's supposed to connect to, unless you're in a network and using DHCP.

DHCP is Dynamic Host Configuration Protocol. On a network, you use DHCP on the network server to automatically assign internal IP addresses to computers as they log into the network. That comes in handy because it's easier to configure a bunch of workstations to grab addresses as they sign on than it is to give them all permanent (i.e. static) addresses and keep track of what's been used and what hasn't. If you accidentally assign the same IP address to two computers, only one of them will be able to get onto the network and it can be a pain to find out which computer is causing the problem. With DHCP, the server is doing all of that work for you.

DHCP can also be used to tell computers on a network what DNS server they're supposed to go to. Unlike IP addresses, it's no problem at all to have all the computers on a network go to the same DNS server. Still, it's easier to have DHCP do it than to set them all up manually.

Answer 2

a dns is a domain name server - something like a mapping between an ip and it's hostname...
yahoo.com for example has the ips 66.94.234.13 and 216.109.112.135 - when you type the address www.yahoo.com in your browser, the dns client in your machine contacts the dns server to get the ip address corresponding to yahoo.com... routers are layer 3 devices - they understand only ip addresses, hence to route your request across the internet, the ip address is required...
a dns can be compared to a phone book - your telephone doesn't understand names, only numbers... so to call a person you check up a phone book and find that persons number... similarly the computer checks with the dns to find that site's (or host's) ip...
a DHCP (dynamic host configuration protocol) is a server usually hosted on the router or gateway to a network, which assigns an ip address, a gateway address, a subnet mask and 2 dns (primary and secondary) addresses every host in the network using a DORA(discover-offer-request- acknowledge) process... the ip address given by the dhcp is set for a fixed time (say 2 days) called a lease... after around 60% of the lease has expired, the dhcp checks with the host to see if the host still needs the ip, if it does, the lease is extended and if it doesnt, the lease expires and the host has to go through the DORA process all over again...
if you goto start-run-cmd(on a win xp computer) and in the command prompt type ipconfig/all, you'll see the ip, subnet, gateway, dhcp address, dns1 and lease information

-mav

Answer 3

DNS:

On the Internet, the Domain Name Service (DNS) stores and associates many types of information with domain names; most importantly, it translates domain names (computer hostnames) to IP addresses. It also lists mail exchange servers accepting e-mail for each domain. In providing a worldwide keyword-based redirection service, DNS is an essential component of contemporary Internet use.

Pre-eminently, the DNS makes it possible to assign Internet destinations to the human organization or concern they represent, independently of the physical routing hierarchy represented by the numerical IP address. Because of this, hyperlinks and Internet contact information can remain the same, whatever the current IP routing arrangements may be, and can take a human-readable form (such as Yahoo.com) which is rather easier to remember than an IP address (such as 66.230.200.100). People take advantage of this when they recite meaningful URLs and e-mail addresses without caring how the machine will actually locate them.

The DNS also distributes the responsibility for assigning domain names and mapping them to IP networks by allowing an authoritative server for each domain to keep track of its own changes, avoiding the need for a central registrar to be continually consulted and updated.



DHCP:

DHCP is a set of rules used by communications devices such as a computer, router or network adapter to allow the device to request and obtain an IP address from a server which has a list of addresses available for assignment.

DHCP is a protocol used by networked computers (clients) to obtain IP addresses and other parameters such as the default gateway, subnet mask, and IP addresses of DNS servers from a DHCP server. It facilitates access to a network because these settings would otherwise have to be made manually for the client to participate in the network.

The DHCP server ensures that all IP addresses are unique, e.g., no IP address is assigned to a second client while the first client's assignment is valid (its lease has not expired). Thus IP address pool management is done by the server and not by a human network administrator.

DHCP emerged as a standard protocol in October 1993. As of 2006, RFC 2131 provides the latest ([dated March 1997]) DHCP definition. DHCP functionally became a successor to the older BOOTP protocol, whose leases were given for infinite time and did not support options. Due to the backward-compatibility of DHCP, very few networks continue to use pure BOOTP.

Answer 4

in a very abstract level definition ,
dns- domain name system ,maps IP address to the name (e.g www.yahoo.com) and visa versa... the network works based on IP but its not easy to remember the IPs so we use the names like www.yahoo.com,www.google.com, so there has to be something that maps the IP address to the respective names, dns fulfils that need.

dhcp-dynamic host configuration protocol, this is used to manage the IPs. dhcp server on the network assigns IP addresses to the hosts. When the host does not have an ip address set static it goes to the dhcp server when booted to get an ip address. The dhcp server assigns a unique IP address with a certain lease period.

well i can go on.. its vast .. but i guess for basic understanding this will suffice...

Answer 5

DNS-> Domain naming service

Will translate IP address to the particular domain name
216.109.112.135 to yahoo.com

DHCP-> Dynamic host control protocol

Used to search for the domain names in the network