topic Re: Q: DNS query format in Operating System - Linux

Q: DNS query format

Vitaly Karasik_1 — Thu, 25 Jan 2007 10:59:45 GMT

[sorry for off-topic]

Is this DNS query correct?:

Domain Name System (query)
Transaction ID: 0x938a
Flags: 0x0110 (Standard query)
0... .... .... .... = Response: Message is a query
.000 0... .... .... = Opcode: Standard query (0)
.... ..0. .... .... = Truncated: Message is not truncated
.... ...1 .... .... = Recursion desired: Do query recursively
.... .... .0.. .... = Z: reserved (0)
.... .... ...1 .... = Non-authenticated data OK: Non-authenticated data is acceptable
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
1.2.3.e164.arpa: type NAPTR, class IN

According to RFC1035, 3 reserved bits should be 0s. But in my example second bit is 1 and even interpreted by Etherreal as "Non-authenticated data OK" flag.
So is this a legal query?

(the reason I'm asking is: this query is coming from forward-only zone in bind9. We have custom ENUM server which doesn't accept this query. )

TIA,
Vitaly

Re: Q: DNS query format

Andrew C Fieldsend — Fri, 26 Jan 2007 05:52:07 GMT

I'd be surprised if BIND 9 were sending invalid queries, bearing in mind how common it is used.

Page 26 of RFC1035 gives the field definitions, and says that the 3 reserved (Z) bits follow the AA, TC, RD, and RA bits.

Andy

Re: Q: DNS query format

Steven E. Protter — Fri, 26 Jan 2007 06:43:29 GMT

Shalom Vitaly,

If you nice folks who know where the RFC is could share a link, I'm willing to put in the time to read it. I do doubt that bind itself is making an invalid query. If I were a betting man I'd bet on a windows box making bad queries.

Mazel Tov bben chadash Vitay.

Shmuel

Re: Q: DNS query format

Andrew C Fieldsend — Fri, 26 Jan 2007 06:46:11 GMT

You can find all of the RFCs at http://www.ietf.org/rfc.

Andy

Re: Q: DNS query format

Huc_1 — Fri, 26 Jan 2007 08:13:33 GMT

Hi

Prefer this link http://rfc.net/rfc1183.html
but, depends on how you like your eggs !

I tryed to read the above rfc but fell a sleeeep on my keybord got azerty (French keyboard here) written all across my forehead... a well best luck next time around.

Jean-Pierre Huc

Re: Q: DNS query format

Vitaly Karasik_1 — Wed, 14 Apr 2010 08:50:29 GMT

old