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I am studying about DNS servers, but have not clear idea about some parts of DNS message which are pointed in following figure:

enter image description here

One of the things I am not clear about is Questions. Can there be multiple entries in this section (of DNS message)? Means can there be number of questions more than one (in one DNS query)? If yes, then how? or in which situations? Because, what I have understood, in normal DNS query only ONE question should be there. Then how can there be multiple questions there (in Questions section of DNS message of ONE query)?

And other thing is what information is contained in Authority and Additional information sections.

Please explain in detail and in an easy-to-understand language from a layman's perspective.

EDITs:

  • Can there be multiple entries in this section? ==> Can there be multiple entries in this section (of DNS message)?
  • can there be number of questions more than one? ==> can there be number of questions more than one (in one DNS query)?
  • in normal query only question should be there ==> in normal DNS query only ONE question should be there
  • Then how can there be multiple questions there? ==> Then how can there be multiple questions there (in Questions section of DNS message of ONE query)?
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Whilst the DNS packet format technically supports multiple questions, in practise there can only be one, and the vast majority of servers will return FORMERR if more than one is seen.

In part this is because there are no defined semantics for what RCODE to return if the multiple questions were to result in different responses (e.g. NOERROR vs NXDOMAIN).

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