Benefits of Using Domain Name System (DNS)

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Benefits of Using Domain Name System (DNS)

• DNS names are user friendly.
• DNS names are more consistent than IP addresses.
• DNS allows the same naming convention as the
  Internet.

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Domain Name Space
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Examples of Second-Level Domains

• Ed.gov
• Microsoft.com
• Stanford.edu
• W3.org

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Host Names

• Refer to specific computers on the Internet or an
  intranet
• The leftmost portion of a fully qualified domain
  name (FQDN), such as Computer1.sales.microsoft.com
  
• Does not have to match the computer name

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Domain Naming Guidelines

• Limit the number of domain levels.
• Use unique names.
• Use simple names.
• Avoid lengthy domain names.

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Domain Naming Guidelines (continued)

• Use standard DNS characters and Unicode
  characters
• Microsoft Windows 2000 supports AZ, az, 09,
  hyphen (-)
• Supports Unicode character set

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Zones
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Name Servers

• Store the zone database file
• Store the database file(s) for one or multiple
  zones
• Have authority for the domain name space that the
  zone encompasses
• Are required in every zone

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Primary Zone Database File

• A name server in each domain contains the master
  database file.
• Changes to a zone are performed on it.
• Multiple name servers act as a backup.

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Benefits of Multiple Name Servers

• Provide zone transfers
• Provide redundancy
• Improve access speed
• Reduce the load

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Name Resolution

• Resolving names to IP addresses
• DNS resolves www.microsoft.com to an IP address

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Forward Lookup Query
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Name Server Caching
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Reverse Lookup Query

• Maps an IP address to a name.
• Used by troubleshooting tools such as the
  nslookup utility.
• Some applications implement security based on the
  ability to connect to names.

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The in-addr.arpa Domain
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Introduction to DNS Clients

• DNS is a distributed database used in TCP/IP
  networks.
• TCP/IP must be installed to use DNS.

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Internet Protocol (TCP/IP) Properties Dialog Box