Subject: Re: Usenet Censorship

From: Vernon Schryver <[email-masked]>
Date: Wed, 18 Nov 1998 09:05:56 -0700 (MST)

> From: [email-masked]

> ...
>                      expects certain subscribers with personal
>                      agendas to siphon Clean News's cancel
>                      messages into the general Usenet feed. 
>
>                      "Let's say that Reverend Falwell had an
>                      ISP," he says. Such a misuse of the
>                      cancel messages would, however, be "not
>                      my issue." 
>
> I can just imagine 500,000 cancel messages/day being fired back and
> forth between servers - obviously not a good idea.  

By long standing tradition, before making predictions of the death of
the net, it is a good idea to check some of the technical details.

First, by public accounts from those running the netnews anti-spam systems
last winter, 500K cancels/day would have been a major reduction in the
number of daily cancels they were issuing.  I assume the anti-spam robots
are still running at those old rates, although I've not checked for months.

Second, it is trivial to tell your computers to ignore a stream of cancel
messages that do not have forged Path: lines no matter where you are on
the net.  That fact is fundamental to the claims that the established
streams of spam cancels are and the various streams of black-list cancels
against various ISP's such as UUNET were advisary or voluntary.  (Of
course, it is also trivial to turn off all cancels, which puts the lie to
the claims of spammers and kooky "freedom knights" that spam cancels are
censorship.)  Any leaks of this or any other cancel feed, whether
intentionally leaked or not, no matter how kooky, would not be a problem
for more than a matter of minutes at any competantly run system.

Third, should the stream of cancels have forged headers, it is trivial
for the neighbors of the source to deal with it, provided the source does
not move around.  If the immediate neighbors do not deal with such
problems, they are treated as part of the problem and dealt with by their
neighbors.  Kooks, idiots, and cults have tried to kill netnews many times
with spews of cancel messages with forged headers, and failed.  Netnews
has been killed by its success, by turning into a 90's CB radio, but that's
another story.

Fourth, what's this about cancel messages "being fired back and forth"?
Cancelling a cancel message doesn't work.

Vernon Schryver    [email-masked]

---

From: Karl Denninger <[email-masked]>
Date: Wed, 18 Nov 1998 10:45:16 -0600

> the net, it is a good idea to check some of the technical details.

:-)

> are still running at those old rates, although I've not checked for months.

Correct.  They are, if the spam/cancel stats I have seen from Diablo reports
on servers with open HTML versions of that (many) are to be believed.

> for more than a matter of minutes at any competantly run system.

Yep.

> not move around.  

Moving around the source of cancels at this kind of volume is rather
difficult. :-)

> Cancelling a cancel message doesn't work.

No, but poisoning the history file so that the cancel is ignored (ie: you
post a binary with message ID "<[email-masked]>", and you know that the
cancel will prepend "cancel." to the message ID, so you ALSO send another
message (headers only?) with that ID out at the same time) does work.

For this reason randomizing the message ID used for the cancel becomes
necessary, with probes to detect people trying to do this - and
synchronizing the cancel-emitters to "mutate" the ID format.

--
-- 
Karl Denninger ([email-masked]) http://www.mcs.net/~karl
I ain't even *authorized* to speak for anyone other than myself, so give
up now on trying to associate my words with any particular organization.

---

From: Karl Denninger <[email-masked]>
Date: Wed, 18 Nov 1998 10:45:16 -0600

:-)

Yep.