Subject: Last Call: Root Name Server Operational Requirements to BCP

From: The IESG <[email-masked]>
Date: Fri, 25 Feb 2000 09:38:09 -0500

The IESG has received a request from the Domain Name Server Operations
Working Group to consider Root Name Server Operational Requirements
<draft-ietf-dnsop-root-opreq-03.txt> as a BCP.

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action.  Please send any comments to the
[email-masked] or [email-masked] mailing lists by March 25, 2000.

Files can be obtained via
http://www.ietf.org/internet-drafts/draft-ietf-dnsop-root-opreq-03.txt

---

From: Robert Elz <[email-masked]>
Date: Mon, 28 Feb 2000 19:11:36 +1100

Date:        Fri, 25 Feb 2000 09:38:09 -0500
    From:        The IESG <[email-masked]>
    Message-ID:  <[email-masked]>

  | The IESG has received a request from the Domain Name Server Operations
  | Working Group to consider Root Name Server Operational Requirements
  | <draft-ietf-dnsop-root-opreq-03.txt> as a BCP.

One minor point - section 2.8 ...

   2.8 Servers MUST generate checksums when sending UDP datagrams and
       MUST verify checksums when receiving UDP datagrams.

could perhaps be read as suggesting that a root server must discard a
UDP packet received without a checksum (checksum field set to 0), as in
such a packet the checksum cannot be verified.   I see no reason why a
root server shouldn't process such requests, however dumb some may consider
sending such things.   So, I'd propose rewording that sentence to...

   2.8 Servers MUST generate checksums when sending UDP datagrams and
       MUST verify checksums when receiving UDP datagrams containing
       a non-zero checksum.

to make it quite clear that the point is that the servers aren't allowed
to "optimise" away the checksum check, which I assume was the point.

kre

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From: Randy Bush <[email-masked]>
Date: Mon, 28 Feb 2000 10:49:35 -0800

[ note cc:s narrowed to those assumed actually interested ]

> such a packet the checksum cannot be verified.

i suspect that was the intent.  why respond to garbage?

> I see no reason why a root server shouldn't process such requests, however
> dumb some may consider sending such things.

perls before swine?

>  So, I'd propose rewording that sentence to...
> 

i can live with it.  let's see what co-authors have to say.

randy

---

From: Robert Elz <[email-masked]>
Date: Tue, 29 Feb 2000 16:22:21 +1100

Date:        Mon, 28 Feb 2000 10:49:35 -0800
    From:        Randy Bush <[email-masked]>
    Message-ID:  <[email-masked]>

  | i suspect that was the intent.  why respond to garbage?

If you don't respond, you, or some other root server, is just going to get the
query again, just the same (most of the time).

There are two situations - either the packet has been mangled somehow,
and the lack of the checksum means you can't detect that, or the packet
is correct but just comes from someone who doesn't bother to checksum
udp packets.   In the former case, the reply is likely wasted (even then
not necessarily, the corruption might be to some part that would be irrelevant
to a reply from a root server) - there will need to be a retransmit anyway,
and a new reply.   Fortunately, that shouldn't happen often (packets that
udp checksums catch, which link level checksums haven't caught, are fairly
rare).   In the latter case, the reply will be just fine, and communications
continue, and the root server stops being bothered by this query.

  | perls before swine?

I doubt that the root servers are the proper place to evangalise for the
use of udp checksums...

kre

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From: Robert Elz <[email-masked]>
Date: Tue, 29 Feb 2000 16:25:38 +1100

| [ note cc:s narrowed to those assumed actually interested ]

Oh, forgot to say that my message was to the places requested in the
last call, plus the WG list, and ...

  | i suspect that was the intent.

And also forgot to say, that if the "other" interpretation was the
intent, then that is also not clear, and the wording ought be fixed
to make that plain "root servers must discard dagagrams with a
zero UDP checksum, and must verify the checksum otherwise" or something
(better words that that can be found, I'm sure).

So either way, some change ought be made to that paragraph/sentence.

kre

---

From: Randy Bush <[email-masked]>
Date: Sat, 04 Mar 2000 20:09:34 -0800

>        MUST verify checksums when receiving UDP datagrams containing

draft-ietf-dnsop-root-opreq-04.txt has the requested change and should
appear in a day or three.

randy