A while ago, I was out for lunch with a few colleagues, when one of them received a call on his mobile. It was a tele-marketing call, promoting a rival mobile services brand. It seemed obvious that the marketing agency was calling a sequence of phone numbers selected randomly.

Irritating, disturbing and intrusive. I’m sure you agree. Much to my surprise however, my friend Cyrus proceeded to engage the caller in conversation. He spoke calmly and even agreeably, asked questions and expressed an interest in exploring a corporate deal. A few minutes of talk and he said that he would place an order - as long as they offered it to him at price “x” (x being a ridiculously low number). So ridiculous, that one would be completely embarassed or simply laugh out loud. Needless to say, the conversation came to an abrupt end.

Amidst the laughter and chatter that followed, Cyrus explained that he’d heard, if you wasted the caller’s time often enough, your number got “black listed”, and since most of these marketing lists sooner or later get shared with others, the chances of you being called like this, minimize. Sounds wonderful! :)

The technology biased part of my mind immediately recognized this principle as tarpitting. In the world of email, we’ve all experienced the ill effects receiving spam. A major reason that spammers spam is that they find the process extremely cost & time effective. I mean spammers send mass email to a whole lot of people, very quickly, very easily and at very low costs.

Using tarpitting, we could make this process a little less attractive for the spammers. The principle is the same as in my little story above.

Lets assume that a mailserver has determined (via other methods) that it is receiving spam from some machines. One way to respond would be to reject connections from these hosts. Effective and often done. But that would simply result in the spammers ignoring you and continuing to target someone else (besides it won’t help my example :)).

If our mailserver uses tarpitting however, it will continue to accept connections from the spammers, but it will treat these connections different from good ones. How? Email transfer between machines happens using standard protocols. If our server responds slowly and sluggishly to the spammers, then we have tied up their connections, wasted some of their resources and made their operations more expensive, in terms of time and eventually money.

Of course the whole process is not as simple as it sounds, but my intention was to share the principle.

So the next time you get an annoying call on your phone, don’t just hang up. Try some tarpitting instead… :)

This entry was posted on Tuesday, April 19th, 2005 at 1:41 pm and is filed under General, Internet. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.