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Domain
A domain is a logical grouping of users, computers, peripherals, network services, and security settings. From the perspective of network service access, domains are usually centralized network environments where authentication is governed by a domain controller. In Windows Server-based networks, the domain is powered by the AD DS role.
Figure 4.6 presents the step in the Active Directory Domain Services Configuration Wizard to specify the domain:
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Figure 4.6. Setting up a root domain in Windows Server 2016
You must understand that there is a profound difference in the meaning of domain in the context of a directory domain or a domain server, and in the context of domain name. The former means a database of users, servers, devices, and resources within a specific collection of such things. The latter means the logical naming system that governs the internet, including web servers and websites.