APPLICATION LAYER
INTRODUCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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1 & 10
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0 & 1
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10 & 0
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1 & 0
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Detailed explanation-1: -The first flag bit signifies query or response. A “0” indicates a query, and hence a “1” a response. The DNS header is 12 bytes long.
Detailed explanation-2: -DNS message is relatively simple: the browser queries a domain name and gets an IP address. If a DNS server doesn’t recognize the domain name, it will pass the query along to the following DNS server. Later, when receiving a response, it carries the response to the browser.
Detailed explanation-3: -15.3 The DNS Question (Question Section) A value of zero indicates the end of the name field.
Detailed explanation-4: -QR A one bit field that specifies whether this message is a query (), or a response (). Obviously, you should use for your requests, and expect to see a in the response you receive. OPCODE A four bit field that specifies kind of query in this message. You should use , representing a standard query.