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us If you already understand what DNS is and does and how it
fits into the greater scheme of things - skip this chapter.
Without a Name Service there would simply not be a viable
Internet. To understand why we need to look at what DNS does and
how and why it evolved. A DNS translates (or maps) the name of a
resource to its physical IP address - typically referred to as
forward mapping A DNS can also translate the physical IP address
to the name of a resource - typically called reverse mapping.
Remember that the Internet (or any network for that matter)
works by allocating every point (host, server, router, interface
etc.) a physical IP address (which may be locally unique or
globally unique). Without DNS every host (PC) which wanted to
access a resource on the network (Internet), say a simple web
page e.g. www.thing.com, would need to know its physical IP
address. With 100 of millions of hosts and billions of web pages
it is an impossible task -