General DNS questions

[Brad Knowles]

At 9:28 PM -0600 5/21/01, Matt Simerson wrote:

>  By definition a recursive (or stub) resolver has no concept of the TLD and
>  doesn't have the intelligence to issue iterative queries or follow
>  referrals. Therefore, stub resolvers (as MacTCP and Open Transport are)
>  issue recursive queries, just like nearly every other DNS client does.

	Recursive resolver != stub resolver

	A "stub resolver" has virtually no intelligence whatsoever, and 
asks that the nameserver do everything for it, including all 
recursion.  A "recursive resolver" has a little more intelligence and 
can handle it's own recursion, but no more.

	The former is very common, and found on all OSes I know of, save 
Macintosh -- where they have decided to implement the latter.

>>  Indeed, IIRC the early versions would actually "cache" the data they
>>  looked up in a local HOSTS.TXT file, so that they would never again
>>  have to go looking for that information.
>
>  Nope. I've never even seen such a crazy thing. MacTCP is the beginning of
>  TCP on the Macintosh series of computers and I've been using MacOS since
>  before MacTCP was available.

	I've been a Mac fan since early 1984, when I saw a demo of one of 
the very first 128K Macs -- five minutes with MacPaint and MacWrite 
(the only two applications which existed at that point) was enough to 
convince me that this was the future of computing.  I've been 
actively using them since the original Mac 512K (with the 400KB 
floppy drive, not the 512KE with the 800KB floppy drive).

	I distinctly remember MacTCP doing illegal local caching, and as 
Chip reminded me, that stuff was stored in the "MacTCP DNR" file.

>  That is utter nonsense. If you talked to Garry about this I would think he'd
>  have set you straight a long time ago. A little research on Garry will also
>  reveal that he was receptive to the suggestions of Mac users (and the
>  internet community as a whole).

	What I gave Garry grief about was the illegal caching, and the 
bizarre choice of having a recursive resolver instead of a plain stub 
resolver.

	While I don't believe that the recursive resolver issue was 
solved with Open Transport, at least the illegal caching was.

>  You have got to be thinking of another OS. MacOS has never uses a hosts.txt
>  file.

	Sorry, I was confused.  It was the "MacTCP DNR" file.  Indeed, 
after all this time, some applications *still* expect this file to 
exist, and will not function if it has been removed -- even though it 
no longer serves any purpose.

-- 
Brad Knowles, <brad.knowles at skynet.be>

/*        efdtt.c  Author:  Charles M. Hannum <root at ihack.net>          */
/*       Represented as 1045 digit prime number by Phil Carmody         */
/*     Prime as DNS cname chain by Roy Arends and Walter Belgers        */
/*                                                                      */
/*     Usage is:  cat title-key scrambled.vob | efdtt >clear.vob        */
/*   where title-key = "153 2 8 105 225" or other similar 5-byte key    */

dig decss.friet.org|perl -ne'if(/^x/){s/[x.]//g;print pack(H124,$_)}'