How to find initiating host address?

["Àü¿ìÁ÷" <chun@comeng.chungnam.ac.kr>]

I have a question on the operation of resolver and name server.

As far as I understand, the resolver of a host, say A,
sends query to name server in "recursive" mode.
Then the name server, say firstNS,  performs the query in referal
manner,
and it queries to other name servers, say NS2, .., lastND,
accroding to domain name.
Is it correct?

Then, the lastNS has no clue on which host initially generate the query.

Only what the lastNS knows is the firstNS that has performed the query
on the behalf of the initiating host.

My next question is:
Is there any method for the lastNS to find out what is the host that
initiated
the query?
This may useful to reply differently according to the initiator.
For example, the lastNS may have a list qualified host to reply, and
then
the lastNS veryfies the host address before replying.

If there is no mechnism in the existing internet standard,
is there any RFCs related with this issue?

Please let me know if anyone who has idea on extending the DNS standard.

IMHO, a field, "initiator" or something, may be inserted in DNS query,
and
this field must be copied to recursibe querries.

Thanks in advance!