NA Lesson – 20

Implementing a DNS Name Resolution Identity

How many DNS servers?

There are many reasons why we should go for multiple servers.A few aming these reasons are given below:

·         Providing redundancy

·         Improving performance

·         Balancing traffic load

·         Reducing WAN traffic

·         Delegating authority

·         Supporting Active Directory

What are the major components?

Major components of a DNS implemented network infrastructure are given below:

        i.            DNS Server

      ii.            DNS zones

    iii.            DNS resolvers

     iv.            Resource records

i.DNS Servers

A DNS server is a computer that runs a DNS server program, such as the DNS Server

service or Berkeley Internet Name Domain (BIND).

A DNS server is authoritative for a zone if it hosts the zone, either as a primary or secondary DNS server. A server is authoritative for a domain when that server relies on locally configured resource records.

ii.DNS Zones

A DNS zone is a contiguous portion of a namespace for which a server is authoritative. A server can be authoritative for one or more zones, and a zone can contain one or more contiguous domains.

Zone files contain resource records for the zones for which a server is authoritative. In many DNS server implementations, zone data is stored in text files; however, DNS servers running on Windows 2000 or Windows Server 2003 domain controllers can also store zone  information in Active Directory.

iii.DNS Resolvers

A DNS resolver is a service that uses the DNS protocol to query for information from DNS servers. DNS resolvers communicate with either remote DNS servers or the DNS server program running on the local computer.

In Windows Server 2003, the function of the DNS resolver is performed by the DNS Client service. Besides acting as a DNS resolver, the DNS Client service provides the added function of caching DNS mappings

iv.Resource Records

Resource records are DNS database entries that are used to answer DNS client queries. Each DNS server contains the resource records it needs to answer queries for its portion of the DNS namespace. Resource records are each described as a specific record type, such as host address (A), alias (CNAME), and mail exchanger (MX).

Q. Describe briefly major components of a DNS implemented network infrastructure?