Check out the new USENIX Web site.

USENIX Home . About USENIX . Events . membership . Publications . Students
LISA '03 — Abstract

Pp. 223-236 of the Proceedings

Distributed Tarpitting: Impeding Spam Across Multiple Servers
Award Paper!

Tim Hunter, Paul Terry, and Alan Judge,


This paper describes an Irish ISP's attempts to combat the abuse of resources caused by unsolicited commercial email. We describe the extension of a multicast system, used to implement POP-before-SMTP relaying, to share information about remote mail servers between multiple mail systems. The information may then be used to tarpit abusive servers - placing delays between SMTP protocol answers thus mitigating their impact on our systems. We then examine how effective this has been, and come up with some ideas for future development.

We also discuss building a policy around this and other measures we use to combat spam. An ISP is in the business of sending and receiving mail - this makes slowing or blocking mail a delicate subject.

  • View the full text of this paper in HTML or PDF. The Proceedings are published as a collective work, © 2003 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.

  • If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.

To become a USENIX Member, please see our Membership Information.

?Need help? Use our Contacts page.

Last changed: 7 Nov. 2003 aw
Technical Program
LISA '03 Home