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Resolving Names and Numbers

invisible.xbm Ok, computers can be referred to by either their FQDN or their Internet address. How can one user be expected to remember them all?

They aren't. The Internet is designed so that one can use either method. Since humans find it much more natural to deal with words than numbers in most cases, the FQDN for each host is mapped to its Internet number. Each domain is served by a computer within that domain, which provides all of the necessary information to go from a domain name to an IP address, and vice-versa. For example, when someone refers to foosun.bar.com, the resolver knows that it should ask the system foovax.bar.com about systems in bar.com. It asks what Internet address foosun.bar.com has; if the name foosun.bar.com really exists, foovax will send back its number. All of this "magic" happens behind the scenes. invisible.xbm invisible.xbm

Rarely will a user have to remember the Internet number of a site (although often you'll catch yourself remembering an apparently obscure number, simply because you've accessed the system frequently). However, you will remember a substantial number of FQDNs. It will eventually reach a point when you are able to make a reasonably accurate guess at what domain name a certain college, university, or company might have, given just their name.

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