It is critical to understand the domain name space concept because this is what managing domains (as in Microsoft domains) is going to be all about with Windows NT 5.0 .

What is DNS (Domain Name System)?

DNS computer names consist of two parts: a host name and a domain name which combine to form a FQDN (fully qualified domain name). Example: moon.sun.com. Moon is the host name and sun.com is the domain name. FQDN's are user-friendly conveniences that represent the dotted decimal notation of IP addresses that are not required for the operation of communication, unlike NetBIOS names. You get Internet domain names at Internic.

How does DNS Server Service resolve FQDN's into IP addresses?

DNS Server Service is used to ultimately resolve FQDN into IP addresses that is then used by the "networks that connect LAN's together." Example: You can use IE (Internet Explorer) to open moon.sun.com, and a DNS server can resolve this friendly name to the correct IP address on the Internet. The computer must know the IP address of the DNS before it can use TCP/IP to connect to the Internet.

What are the benefits of DNS?

• access to Unixxxxxx using friendly names
• Internet connection using Internet naming conventions
• maintain consistent hierarchial naming scheme across your organization

How does DNS work? (client/server)

DNS Servers (name servers) contain information about of the DNS database (zone) and make information available to Clients (resolvers)

What is Domain Name Space?

DNS database is a tree structure called domain name space. Each domain (node in the tree structure) is named and can contain subdomains. The domain name identifies the domain's position in the database in relation to to its parent domain. A period separates each part of the name for each network node in the DNS domain.   For example: "globetrotting.com." "globetrotting" specifies the globetrotting subdomain whose parent is the "com" domain.

Why use the period at the end?

A period separates each part of the name for each network node in the DNS domain. The root node in a DNS database is unnamed. The root node is referenced in DNS names with a trailing period (.). Example: "moon.sun.com." It is the period after com that denotes the DNS root node.

How are Root and Top-Level Domains managed?

Root and Top level domains are managed by Internic. Top level is .com and .net and .org etc ; the root is the borg! ;-) DNS name space below top level is delegated to organizations by Internic. These organizations can further subdivide the name space and delegate responsibility down the hierarchial tree structure.

Getting in the "Zone"

Administrative unit for DNS is the zone. Zone is subtree of DNS database that is administered as a single separate entity. It consists of a single domain or domain with subdomains. Lower level subdomains of zone can be split into separate zones and so on.
For example: .com is the top level. globetrotting makes this the globetrotting domain and the globetrotting zone.

What is the syntax for FQDN's (bear with the cave scrawlings)?

    .com
        |
        |----------|
                   |
           globetrotting
                   |
                   |
                   ----------------------------------------
                                   |                       |
                                   |                       |
                            generation           connect
                                   |
                                   |
                                wired

FQDN: wired.generation.globetrotting.com.
FQDN: connect.globetrotting.com.

What are the rules for FQDN's?

• Besides the root, each node in DNS database has a name (label) of up to 63 characters
• Each subdomain must have a unique name within its parent domain