Ques : Describe understanding of DNS

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 Understanding DNS

The basic function of name server is to answer queries by providing the information
that those queries request. A DNS name server primarily translates domain and host
names into IP addresses. Each domain is typically represented by a least two DNS
servers. The following are different types of DNS servers:

• Primary (master) name server contains authoritative information about the
domains that it serves. In response to queries for information about its domains,
this server provides that information marked as being authoritative. The primary
is the ultimate source for data about the domain. The secondary name server only
carries the same authority in that it has received and loaded a complete set of
domain information from the primary.

• Secondary (slave) name server
gets all information for the domain from the
primary. As is the case for the primary, DNS considers the secondary information
about the domain that it serves authoritative.

• Caching name server simply caches the information it receives about the
locations of hosts and domains. It holds information that it obtains from other
authoritative servers and reuses that information until the information expires.

• Forwarding name server is essentially a caching name server but is useful in
cases where computers lie behind a firewall and in which only one computer can
make DNS queries outside that firewall on behalf of all the internal computers.

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