Anoying Peter Whalley Spam messages.

Paul Howarth paul at city-fan.org
Mon Apr 4 20:39:10 UTC 2005


On Mon, 2005-04-04 at 15:29 -0500, Aleksandar Milivojevic wrote:
> David Hoffman wrote:
> 
> > I have been using TMDA on one of my other accounts since March 15,
> > 2003, and since then, I have received a total of 6 spams. Over 114000
> > have been blocked by the first methods, and another 13400+ were
> > blocked by Spamassassin. The remaining 1300+ that passed those checks
> > were from spammers not responding to TMDA challenges. The six that got
> > through were because spammers used real e-mail addresses and got the
> > challenge messages and then responded to them.
> 
> The question is how many legitimate messages you lost in past years, 
> because people who sent them were not willing to respond to your 
> chalanges?  Before you start convincing people how great TMDA is, couple 
> of facts:
> 
> TMDA is advertised to have zero false positives.  This is lie.  Not all 
> people will be willing to respond to challenges.  Some will simply 
> ignore them because it is a waste of sender's time.  There will be false 
> positives.  Users of TMDA are simply loosing some of the legitimate (and 
> possibly valuable) email sent to them.  This is especially true when you 
> post to the list, and people reply off the list for whatever reason.
> 
> TMDA challenges often visually look like spam or other types of 
> commercial mail.  HTML email with nice graphics and click here link. 
> Some folks will not even read it before deleting it.  They'll never know 
> they even got the challange.  More lost email for you.
> 
> Many TMDA users will tell you "but I haven't had any friend 
> complaining".  It doesn't count.  Friends will recognize your name in 
> headers.  They'll probably read the spam you send them.  They'll 
> probably put with whatever you throw at them.  That is why they are your 
> friends.  It is the people that do not know your name, and you don't 
> know their name, where you start loosing email without ever realizing it.
> 
> TMDA anoys people.  Period.  Even if they reply to chanlenges, most of 
> them are anoyed they had to jump through the loops in order to 
> communicate with you.  The fact you don't know they are anoyed (or don't 
> care to know) doesn't mean they are not anoyed.

My personal opinion is that challenge-response anti-spam filters are a
way of cost-shifting the spam filtering from recipient to (putative)
sender (i.e. usually a forgery these days). In other words, sending
challenges is no better than spamming. So my policy is to acknowledge
challenges for messages I didn't send (spam) and not for mail that I did
send (ham). So challenges sent to me result in either a false negative
(spam) or false positive (ham). And I'm not the only person that does
this.

Paul.
-- 
Paul Howarth <paul at city-fan.org>




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