The DNS server can instruct the client to initiate a domain name query to a specific server.

The DNS server obtains the upper level or root DNS server to which
the domain name belongs and sends it to the client to instruct the
client to initiate a query to this server.

Figure 1 Iterative query


http://localhost:7904/pages/31185199/02/31185199/02/resources/figure/cn_10_01_1430019_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 based on the
configuration and sends it to the client to instruct the client to
initiate the query on this server.

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