MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

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Figure 13-8 The domain namespace is hierarchical in structure.
Root Domain
“ . ”
edu com gov org au
sales.microsoft.com.
Computer1.sales.microsoft.com.
Lesson 2 Understanding the Domain Name System
13-27
At the top of the DNS hierarchy, there is a single domain called the root domain, which
is represented by a single period.
Top-Level Domains
microsoft congress
sales
Computer1
Root domain
Top-level domains
Second-level domains
Top-level domains are two-, three-, or four-character name codes. Top-level domains
are grouped by organization type or geographic location. Top-level domains are controlled
by the Internet Architecture Board (IAB), an Internet authority controlling the
assignment of domain names, among other things. Table 13-4 provides some examples
of top-level domain names.
Table 13-4 Top-Level Domains
Top-Level Domain Description
gov Government organizations
com Commercial organizations
edu Educational institutions
org Noncommercial organizations
au Country code of Australia
Top-level domains can contain second-level domains and host names.