World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0003272227
Reproduction Date:

Title: Spamd  
Author: World Heritage Encyclopedia
Language: English
Subject: OpenBSD, OpenBSD Foundation, Plaid Tongued Devils, OpenOSPFD, OpenSMTPD
Publisher: World Heritage Encyclopedia


spamd is a ISC-licensed lightweight spam-deferral daemon written under the umbrella of the OpenBSD project. spamd works directly with smtp connections, and supports features such as greylisting, minimising false positives compared to a system that does full-body analysis. spamd is designed to work in conjunction with pf(4), and should be fully functional on any POSIX system where pf is available, i.e. OpenBSD, NetBSD, FreeBSD and DragonFly BSD.

Uses and features

Spamd is most useful in preventing inbound spam from reaching mail servers. It can also be used as a partial application level proxy to ensure that external mail servers connecting to internal mail servers behave legitimately. Additionally, spamd can be very useful in preventing outgoing spam from systems that may be compromised or under the control of spammers.

It can be used to block spammers with the use of the following features:

  • Blacklisting: such as the SPEWS database or other lists of IPs, and features including small windows sizes.
  • Tarpitting: this can slow down spam reception considerably and hold connections open for a significant amount of time.
  • Greylisting: this forces email to be delayed for a configurable period, requiring the remote end to resend mail at least once in order for it to be delivered.
  • SpamTrapping / GreyTrapping: this is the seeding of an email address so that spammers can find it, but normal users can not. If the email address is used then the sender must be a spammer and they are black listed.

See also

External links

  • Article: Annoying spammers with pf and spamd
  • Article: Don't run a mail server? Here's how you can still hurt spammers from your home PC. (With video)
  • Introduction and history of tarpitting (from the original author)
  • Peter N. M. Hansteen - PF and spamd
  • - Greylisting with PF and spamd
  • Introduction to spamd (from
  • Installing and configuring spamd (from

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.