Subject: Re: DS and Opt-in - a proposal

From: "Steven M. Bellovin" <[email-masked]>
Date: Thu, 03 Jan 2002 23:02:26 -0500

In message <[email-masked]>, Roy Arends writes
:

>We are not talking about authenticated [denial of] existence in general,
>only about authenticated [denial of] existence of unsecured names.
>
>Imagine going into a tourist office (.city), the only authoritative
>place in town to get the authenticatable, verifiable information from.

Let me point folks at draft-bellovin-dnsext-bloomfilt-00.txt, which is 
designed to address that issue.

(a) Is the issue important enough to be worth introducing a brand-new 
mechanism at this time?

(b) Is the false positive rate acceptable?

(c) If so, is the protocol complexity of this suggestion acceptable?

(d) Is it operationally real?

		--Steve Bellovin, http://www.research.att.com/~smb
		Full text of "Firewalls" book now at http://www.wilyhacker.com

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---

From: Roy Arends <[email-masked]>
Date: Tue, 8 Jan 2002 16:35:11 +0100 (CET)

> (d) Is it operationally real?

The idea of using bloom-filters is interesting, but I've
some small concerns about the following:

wrt loops:

In the paper there is an example of using an url in a resource record:

     https://bloomfilter.ns.example.com?324+3248+23980+89732+...

1) this triggers another lookup, which uses the DNS. What if
   "bloomfilter.ns.example.com" does not exist ? How is that denied ?

2) How is the existence of the bloom resource record containing the url
   denied ?

My 0.02 Euro

Roy Arends
Nominum