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@xxxxxxxxxxxx>
