Subject: [question]What is an accurate meaning of "client" in RFC2181?

From: Hideshi Enokihara <[email-masked]>
Date: Thu, 2 Feb 2006 19:54:50 +0900

Hi all,

I have a question regarding the word "client" in RFC2181.

For example, section 5.2 says,

-------------------
   Should a client receive a response containing RRs from an RRSet with
   differing TTLs, it should treat this as an error.  If the RRSet
   concerned is from a non-authoritative source for this data, the
   client should simply ignore the RRSet, and if the values were
   required, seek to acquire them from an authoritative source.  Clients
   that are configured to send all queries to one, or more, particular
   servers should treat those servers as authoritative for this purpose.
   Should an authoritative source send such a malformed RRSet, the
   client should treat the RRs for all purposes as if all TTLs in the
   RRSet had been set to the value of the lowest TTL in the RRSet.  In
   no case may a server send an RRSet with TTLs not all equal.
-------------------

In this paragraph, the word "clinet" appears four times.
Does all of these "client" mean just only client(simple resolver client)? 
Or, does these "cleint" mean include the server acting as client for the purposes of recursive query resolution?

I think that this word "client" is unclear.

There is a similar problem also in section 9. 
------------------

   Where TC is set, the partial RRSet that would not completely fit may
   be left in the response.  When a DNS client receives a reply with TC
   set, it should ignore that response, and query again, using a
   mechanism, such as a TCP connection, that will permit larger replies.
------------------

What do you think?

Best Regards,
-- 
*************************************
Hideshi Enokihara
IPv6 Business
Network & Software Development Dept.
Yokogawa Electric Corporation

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---

From: Mark Andrews <[email-masked]>
Date: Thu, 02 Feb 2006 23:18:53 +1100

> For example, section 5.2 says,

	It also means the resolver in the nameserver.

	RRset with differing TTLs was a common indication that the
	answer had come from a nameserver that had merged RRsets
	or had got a answer from another nameserver that had merged
	RRsets.

> I think that this word "client" is unclear.

	The DNS is a client / server protocol.  A recursive server
	has a client component that iterates.
 
> There is a similar problem also in section 9. 

	Again this is clear.  If you ask a question over UDP and
	get TC in the response you need to re-ask the question using
	TCP.  The problem then becomes what do you do when you get
	TC over TCP? 

	Mark
 
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: [email-masked]

---

From: Hideshi Enokihara <[email-masked]>
Date: Thu, 2 Feb 2006 22:10:03 +0900

Thank you for your reply.

The purpose of this question is to want to avoid the confusion of the 
meaning of the word "client" and "resolver".

RFC2308 that you wrote doesn't use the word "client". 
The word "resolver" is clearly used instead of "client".

I personally thought that the word "resolver" include "Recursion server" and "Client", and the word "cleint" is just simple client.

Can I think that "Clinet" and "Resolver" are the same meanings in RFC?

Best Regards,

On Thu, 02 Feb 2006 23:18:53 +1100

---

From: Paul Vixie <[email-masked]>
Date: Thu, 02 Feb 2006 14:50:54 +0000

i believe that the terms "client" and "server" are inadequate to describe
the roles of the various protocol agents in DNS, and as in RFC 2136, i
suggest the terms "initiator" and "responder" instead.  the the parts of
RFC 2181 which you've quoted here, "client" really means "initiator".  the
DNS protocol specification must be understood in terms of messages --
their format and meaning.  two messages make up a transaction, and each
transaction is initiated by some protocol agent and responded to by others.