Which of the following is/are true for DNS name resolution?
a. For iterative name resolution, the host may have to send multiple DNS requests to several DNS servers.
b. For recursive name resolution, the host sends a single DNS request to its immediate root DNS server.
c. Host aliasing and load distribution are used for better performance.
d. All of these.
Answers
Answer:
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Answer:
d. All of these.
Explanation:
The DNS server receives a DNS request from a host containing a domain name,
and it returns the corresponding IP address. In iterative name resolution, in response to a DNS
request, the DNS server sends back a response specifying the next DNS server to send the
query. In this way, the host may have to send a number of DNS requests before it gets resolved.
Thus, option (a) is true.
In recursive name resolution, the host sends a DNS request to the next higher level DNS server.
The DNS server in turn recursively forwards the request to its next higher-level DNS server, and
so on, until the request gets resolved. The final reply gets back to the host. Here, the host sends
a single DNS request. Thus, option (b) is also true.
For better performance, multiple DNS servers are used with host aliasing in various levels. This
distributes the total load among several DNS servers. Thus, option (c) is also true.