*[Daniel J Peng on Mon, Aug 28, 2000 at 11:53:39PM -0400]:
> On Mon, Aug 28, 2000 at 10:40:31PM +0530, Suresh Ramasubramanian wrote:
> > You seem to be posting directly from your debian box on a uunet dialup - I
> > suggest you check out http://www.mail-abuse.org/dul for why this is A Bad
> I have never understood how doing this is A Bad Thing. Were it not for
> the MAPS DUL, I could have faster mail delivery, ESMTP features that
I see you haven't understood the rationale of the DUL. The DUL is basically a
list of dialup pools of various ISPs - most of whom _voluntarily_ place those
ip blocks there.
Several enterprising spambags decide to set up a mailserver and dns server on
their desktop (there's 'ratware' like Desktop Server available to do this - see
http://www.spamsites.org for more) - and spam 'direct to MX'.
99% of the smtp connections coming directly to a mx from a dialup ip is spam -
the other 1% being people running linux boxes without setting a smarthost in
their MTA. There is _no_ legitimate reason to accept smtp connections from any
IP block where you know there should be no smtp server running at all - and
hence most ISPs use the DUL to reject smtp connections from dialup ip blocks.
> I fail to see how the measure prevents mail abuse in any way. Why
> can't a spammer simply relay mail through his ISP's mailserver? In
I used to work on Juno's abuse desk - (am now a sysadmin at a major Indian ISP)
so I have some experience of this.
Spammers often do just that - on throwaway ISP accounts (free 25 hour trial
packs and such). Such attempts set off all kinds of alarms - aside from all
the complaints pouring into the postmaster and abuse mailboxes. It is
trivially easy to grep your maillogs and radius logs and boot the guy off -
whereupon he gets another account from elsewhere and resumes spewing.
Other times, he abuses some dumb open relay to spew his crap - and the RBL and
RSS lists help to block them <http://www.mail-abuse.org/rbl> and
<http://www.mail-abuse.org/rss>
> fact, wouldn't it be faster this way? Rather than making a connection
> to yb.mx.aol.com and clmin7-ext.prodigy.com and mail.bigfoot.com and
See above - I agree this was a good thing several years _earlier_ - before
Cantor and Siegel, Spamford Wallace (who has since reformed) and other spambags
made it a bad thing. Right now, all servers I control use the DUL (and the
RBL) and will continue to reject mails sent directly from dialup pools.
before I go on - I'd suggest you read news.admin.net-abuse.email for a while
(or maybe ask the same question there). You'll receive several more (if
slightly (!) more rude) answers to your question.
--
Suresh Ramasubramanian + President, CAUCE India
[EMAIL PROTECTED] + http://india.cauce.org
Not every problem someone has with his girlfriend is necessarily due to
the capitalist mode of production.
-- Herbert Marcuse
