If partial answer is known...

DNS

Client

(Resolver)

query A record, Key=HQ.Opus1.COM

Root

Nameserver

COM

Nameserver

Opus1.COM

Nameserver

cache

no

yes

Nameserver

Answer = 161.44.72.2

DNS nameserver remembers

previous domain responses

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Since we already found the answer for cone.tgv.com we know that we can go directly to tgv.com to learn the answer for hq.tgv.com