DNS requests with Rd flag cleared

Matus UHLAR - fantomas uhlar at fantomas.sk
Sat Nov 5 13:47:43 UTC 2011

On 04.11.11 17:21, patrice.wacrenier at orange.com wrote:
>I have noticed that every request sent by a BIND recursive DNS server
>during its iterative process is sent with rd flag cleared.

Correct. when bind does the resolution, it does not ask other servers 
to do it, only to provide data they have.

>I also noticed that when a zone is of type "forward", the forward is not
>done for requests received with rd flag cleared.

Correct, the 'forward' type means that other servers have to be asked 
to do the resolution.

>In that situation any DNS authoritative server receiving such requests
>(with rd flag cleared) is supposed to answer with NS records

Actually, no. authoritative server is expected to provide data it has. 
If not, it needs not to provide anything (but servfail)

> and will
>never be able neither to transmit any recursive request nor to forward
>the request to some other DNS server.

that's what authoritative server means.

>Are there some possibilities to force a recursive DNS to perform its
>recursive process even for request received with rd flag cleared ?

no. You must do what Phil Meyers advised to you in other reply

Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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