The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites.
DNS implements a distributed database to store this name and address information for all public hosts on the Internet. DNS assumes IP addresses do not change (are statically assigned rather than dynamically assigned).
The DNS database resides on a hierarchy of special database servers. When clients like Web browsers issue requests involving Internet host names, a piece of software called the DNS resolver (usually built into the network operating system) first contacts a DNS server to determine the server's IP address. If the DNS server does not contain the needed mapping, it will in turn forward the request to a different DNS server at the next higher level in the hierarchy. After potentially several forwarding and delegation messages are sent within the DNS hierarchy, the IP address for the given host eventually arrives at the resolver, that in turn completes the request over Internet Protocol.
DNS additionally includes support for caching requests and for redundancy. Most network operating systems support configuration of primary, secondary, and tertiary DNS servers, each of which can service initial requests from clients. ISPs maintain their own DNS servers and use DHCP to automatically configure clients, relieving most home users of the burden of DNS configuration. Also Known As: Domain Name System, Domain Name Service, Domain Name Server
Pretend that you want to drive in your car to your friend's house, you say, "I'm going to Chris's house." You do *NOT* say, "I'm going to 2020 Jamestown Court, Anyville, USA." Right? Because it's difficult to remember all the addresses, we only remember the names. But, to compare your car to your computer, your car can't go anywhere unless it goes to the address. DNS is like the name and not the physical address. E.g. The physical address or IP address is 188.8.131.52 but the DNS is www.yahoo.com. www.yahoo.com is easier to remember huh? That's the point!
Now, DHCP is the system used to give out IP addresses on a network. Let's say you take your laptop to Starbucks. Before you can get to yahoo.com, you have to first connect to the network. Part of the connecting process is getting an IP address for your laptop. DHCP is the system that assigns your laptop an IP address for the Starbucks network.
You can think of DHCP, to continue the car analogy, as like the system that gives your car a license plate number so you can be on the roads and go to John's house.