On 5/18/05, Stewart Stremler <[EMAIL PROTECTED]> wrote:
> begin  quoting m ike as of Wed, May 18, 2005 at 02:52:51PM -0700:
> > > How do you offer 'em up?
> >
> > I guess by making them vulnerable in the same way valid addresses are
> > vulnerable.
> 
> Remember that you don't want to offer anything up that could be confused
> with a "real" address, otherwise valid email from strangers trying to
> reach you would result in a false match...
> 
> If that's acceptable, the easier solution is to simple go to whitelists,
> and be done with it.
> 

Yes!

> > And i guess that there are people who have studied the approaches that
> > spammers take to get addresses.
> 
> Web-pages, usenet, compromised boxes, and purchased lists.
> 
> > > "Honeypot" is the name of the generic concept.
> [snip]
> >                                                                ... but
> > I thought that a honeypot was an intentionally weak spot in a security 
> > system,
> 
> I think of a honeypot as something so sweet and tasty so as to get the
> target to do something unwise.
> 
> > where as the spam tactic is more a needle-in-the-haystack approach, where
> > one intentionally pollutes namespace so that the valid addresses become
> > needles and the spammer has to spam the entire haystack in order reach
> > the needle.
> 
> Set the haystack on fire. Sift the ashes. Finding a needle in a haystack
> is no problem if you're willing to engage in a little destructive behavior;
> and spammers aren't afraid of matches.
> 
> > > How do you choose to ignore the spammers?
> > > Filter on the sender's email address?
> > > Block the IP of the sender?
> >
> > If similar content is received at fictitious addresses, then it
> > is spam.
> 
> So content-based matching?  Is the whole message kept, or just
> a checksum of some sort?  (If the latter, only exact matches
> apply, and spammers have already figured out how to make spam
> "unique" for each user.)
> 
> > > I like the idea of greylisting
> > >
> > I'm not sure what greylisting is
> 
> SMTP has the concept of a "temporary" error -- basically, "I can't take
> this email right now, try back in a couple of hours."
> 
> So greylisting uses this. When someone sends you an email, your mail
> server takes note of who you claim to be, what your IP is, and who
> you are sending to... and then has a 'temporary error', and logs that
> information along with a timestamp.
> 
> Subsequent connections are checked against this data, and once
> a certain amount of time has elapsed (say, four hours), email is
> allowed through, otherwise, there's a temporary failure again.
> 
> Real email gets through -- although, with a four-hour delay the first
> time -- so once you have a relationship with someone, there's no
> problem.  Strangers who are legitmately trying to contact you can
> still do so.  Spammers often use tools that send in a fire-and-forget
> manner -- so they won't try back (no spam!) or they'll stay online
> long enough to be listed in an RBL (no spam!).
> 
> -Stewart "In concept, it's brilliant, simple, and elegant." Stremler
> 


Wow. As much as I don't like "contorting" protocols, that's certainly
acceptable behavior, and does have good effects on some concrete
problems. Very simple too......if I'm not cool enough for you to wait
a few hours....then you're not worth my time.

T


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