The Domain Name System Essays

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The Domain Name System A name that identifies one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used inURL's to identify particular Web pages. For example, in the URL http://www.hotmail.com/ the domain name is hotmail.com. Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited number of such domains. For example: · gov - Government agencies · edu - Educational institutions · org - Organizations (nonprofit) · mil - Military · com - commercial business · net - Network organizations · ca - Canada · th - Thailand Because the Internet is based on IP addresses, not domain names,…show more content…
The resolver gets the hostname and returns the IP address or gets an IP address and looks up a hostname. The resolver returns the IP address before asking the TCP to open a connection or sending a datagram using UDP. DNS Organization The domain name system uses a hierarchical naming scheme known as domain names,which is similar to the Unix filesystem tree. The root of the DNS tree is a special node with a null label. The name of each node (except root) has to be up to 63 characters.The domain name of any node in the tree is the list of labels, starting at that node, working up to the root, using a period ("dot") to separate the labels (individual sections of a name might represent sites or a group, but the domain system simply calls each section a label ). The difference between the Unix filesystem and the tree of the DNS is that in the DNS we start on the ground and "go up" till the root. Writing them in this order makes it possible to compress messages that contain multiple domain names. Thus, the domain name "tau.ac.il" contains three labels: "tau", "ac", and "il". Any suffix of a label in a domain name is also called a domain. In the above example the lowest level domain is "tau.ac.il" (the domain name for the Tel-Aviv University Academic organization in Israel), the second level domain is "ac.il" (the domain name for Academic
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