User manual

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Appendix D
Domain Name System
Basic DNS
The Internet uses a distributed naming system called the Domain
Naming System (DNS). DNS allows us to refer to computers by host
names as well as by Internet Protocol (IP) addresses.
IP addresses are hard to remember and are inconvenient to use. DNS
allows us to use host names and domain names which can resolved to IP
addresses. DNS servers translate host names and domain names (for
example, www.cobalt.com) to an associated IP address (for example,
192.168.1.10.)
For example, Cobalt Networks has registered the domain name
“cobalt.com” for use by our servers “mail.cobalt.com”,
“www.cobalt.com” and others. The host names “mail” and “www”
represent different servers registered in the same domain.
A domain name is a computer name suffix shared by a group of
computers in the same organization. A domain name should be
associated with an IP address through a Forward Lookup record.
Domain names are organized in a hierarchy; this hierarchy includes
your company or server name, and a country code (for example, .uk
or .ca) or a top-level domain (for example, .com or .edu).
A Web site on the server is created with one IP address, one host name
and one domain name that together establish the identity of that Web
site on the Internet.
Each domain name requires a primary domain authority on one DNS
server. A secondary DNS server acts as a backup to the primary. DNS
information is configurable only on the primary server, and not on the
backup server.