Hello,

i quite don't understand Authority RRs.

Using dig to resolve some random A records, my caching DNS server sometimes also return Authority RRs and sometimes not. The number and the type of the returned Authority RRs also vary a lot.

What does control whether Authority RRs are returned or not on a standard client query ? Is it a client or server setting ?

What does control how many Authoriy RRs are returned ?

What does control of the type of the Authority RRs records returned ? Sometimes it's multiple NS, sometimes it's a SOA. It's also often comes with Additional RRs of type A about the Authority RRs NS returned.

I'm really looking for a RFC or kind of describing this.

Thanks.