Subject: DNS Error Codes

From: "Donald E. Eastlake 3rd" <[email-masked]>
Date: Tue, 15 Feb 2000 08:39:54 -0500

Hi,

DNS headers provide for only a four bit error code so EDNS0 added an 8
bit extension, bringing it up to 12 bits, and assigned value 16 for
BADVERS.  Since this is out in an RFC, I think its pretty fixed.

I believe the current tsig draft assignes 16-18 with a different
meaning for 16.  When this was noted, I posted something to the effect
that I thought EDNS won, having gotten there first, and I don't recall
any response to this on the list.

When I updated the tkey draft, I bumped the tsig and tkey error
numbers up by one to avoid the conflict.  This is the dnsext TKEY
draft currently out there.  However, I now understand that there is
enough tsig deployment that this may be a problem.

I have just sent a message to internet-drafts requesting that
<ftp://ftp.pothole.com/pub/dee3/draft-ietf-dnsext-iana-dns-00.txt> be
posted.  This is a minor update, mostly just providing that the IESG
may appoint an expert, in addition to the provisions in earlier
iana-dns drafts.  In it, we did not bump the error codes, and show 16
as multiply assigned with a unified EDNS/OPT, TSIG, TKEY error space.

It seems to me there is a three way choice:

(1) Have a unified error space and bump the tsig and tkey error codes
up by one.  This is the cleanest but may be difficult due to tsig
deployment.

(2) Have a unified error space with the assignment documented in the
new IANA-DNS draft.  This has the wart that code 16 has different
meaning in OPT than in TSIG but it is not clear that this would be
much problem in practice.

(3) Have disjoint OPT and TSIG/TKEY error spaces.  This may seem clean
now but in the long run, I think it would be a disaster.  Presumably
codes <16 would be joint anyway.  And there are bound to be future
cases where the same error needs to be defined in both and there will
be great pressure to use the same valude and/or symbol resulting
eventually in a crazy patchwork of joint and disjoint error numbers.

I suggest we go for option 2.

Whichever way we go, it will be a very minor edit to make the tkey and
iana-dns drafts consistent with the decision.

Donald
=====================================================================
 Donald E. Eastlake 3rd                      [email-masked]
 65 Shindegan Hill Road, RR#1                     +1 914-276-2668(h)
 Carmel, NY 10512 USA                             +1 508-261-5434(w)

to unsubscribe send a message to [email-masked] with
the word 'unsubscribe' in a single line as the message text body.

---

From: James Gilroy <[email-masked]>
Date: Tue, 15 Feb 2000 18:27:19 -0800

I second the vote for option #2.

I just plain missed the conflict and shipped a product with the current TSIG
usage (BADSIG as 16).

The key thing being to track these in the future and make sure that even for
drafts we assign the number and avoid the conflict.

	jim

> -----Original Message-----
> From: Donald E. Eastlake 3rd [mailto:[email-masked]]
> Sent: Tuesday, February 15, 2000 5:40 AM
> To: Domain Names WG
> Cc: [email-masked]
> Subject: DNS Error Codes
> 
> 
> Hi,
>