The required IP address or hostname set is obtained automatically based on a domain name.

The DNS server obtains the upper level or root DNS server to which
the domain name belongs and initiates the recursive query until the
required IP address or hostname set is obtained.

Figure 1 Recursive query


http://localhost:7904/pages/31185199/02/31185199/02/resources/figure/cn_10_01_1430018_fig1.png

If the domain name does not belong to the current DNS server, the DNS
server finds the upper level or root DNS server and initiates a
recursive query based on the configuration until the required IP address
or hostname set is obtained.

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