Книга: Fedora™ Unleashed, 2008 edition

How Nameservers Store DNS Structure Information

How Nameservers Store DNS Structure Information

Information about the structure of the tree and its associated resource records is stored by programs called nameservers. Every domain has an authoritative nameserver that holds a complete local copy of the data for the domain; the domain's administrators are responsible for maintaining the data. A nameserver can also cache information about parts of the tree for which the server has no authority. For administrative convenience, nameservers can delegate authority over certain subdomains to other, independently maintained, nameservers.

The authoritative nameserver for a zone knows about the nameservers to which authority over subdomains has been delegated. The authoritative nameserver might refer queries about the delegated zones to those nameservers. So you can always find authoritative data for a domain by following the chain of delegations of authority from . (the root domain) until you reach an authoritative nameserver for the domain. This is what gives DNS its distributed tree structure.

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