Greylisting

Greylisting is a way to block spam based entirely on the behaviour of the sending server; the content of the message is irrelevant. Greylisting is complementary to other spam filtering techniques such as blacklisting. At its simplest, Greylisting looks at the envelope sender address, the recipient address, and the sending IP address, and defers delivery if these haven't been seen together before; spammers don't usually retry. Greylisting is also less commonly spelt as graylisting.

• About Greylisting
• Greylisting Implementations for Servers
• Products Including Greylisting

Related

• Nolisting
• Spam Tarpitting
• Preventing Spam by User Control

About Greylisting

The Next Step in the Spam Control War: Greylisting - projects.puremagic.com/greylisting/
GreyListing - www.eserv.ru/ru/GreyListing
Greylisting.org - greylisting.org/
Listes grises : livre blanc - sebastien.nameche.fr/spam/greylisting/french.html - French
Le Greylisting - www.ba-cst.com/index.php?option=com_content&task=category&sectionid=5&id=22&Itemid=39/ - French
Experiences with Greylisting - www.ceas.cc/papers-2005/120.pdf
Greylisting stats - www.decf.berkeley.edu/help/mail/greylisting-stats.html
Greylisting performance - users.aber.ac.uk/auj/spam/greyperf.shtml

Greylisting Implementations for Servers

• Greylisting for Sendmail
• Greylisting for qmail
• Greylisting for Exim
• Greylisting for Postfix
• Greylisting for Exchange
• Greylisting SMTP Proxies
• Other Greylisting Implementations

Greylisting for Sendmail

Greylisting Implementation - projects.puremagic.com/greylisting/releases/
milter-greylist - hcpnet.free.fr/milter-greylist/
Installing Greylisting via RelayDelay - www.maynidea.com/sendmail/relaydelay.html
milter-gris - www.milter.info/sendmail/milter-gris/
graymilter - www.acme.com/software/graymilter/
smf-grey - smfs.sourceforge.net/smf-grey.html
J-Chkmail - j-chkmail.ensmp.fr/
scam-grey - www.elandsys.com/scam/
Gross - code.google.com/p/gross/

Greylisting for qmail

qgreylist - www.jonatkins.com/page/software/qgreylist
qmail greylisting - www.datenklause.de/en/software/qgreylistrbl.html
Qmail Greylisting - www.digitaleveryware.com/projects/greylisting/
qmail-greylist-pgsql - qgreylist-pgsql.sourceforge.net/
greylite - mij.oltrelinux.com/net/greylite/

Greylisting for Exim

Exim Greylisting - www.digitaleveryware.com/projects/greylisting/
Exim Greylist - llab.zhitomir.net/?greylist
Greylisting with MySQL and Exim - theinternetco.net/projects/exim/greylist
Adding Greylisting Support - www.tldp.org/HOWTO/Spam-Filtering-for-MX/exim-greylisting.html
Greylisting with Exim - www.sigsegv.cx/exim-greylist-2.html
Bagley: Greylisting for Exim 4 - sourceforge.net/projects/bagley/
greylistd in Debian unstable - packages.debian.org/unstable/mail/greylistd
Greylisting Perl module - users.aber.ac.uk/auj/spam/
Easy Greylisting Without A Database - wiki.exim.org/DbLessGreyListing
Fast Gray List Mini Tutorial (MySQL Edition) - wiki.exim.org/FastGrayListMiniTutorial
Simple Universal Greylist - www.schlittermann.de/doc/grey.shtml
Poor man's whitelisting with Exim and SQLite - plonk.de/sw/exim/greylist.txt
Gross - code.google.com/p/gross/

Greylisting for Postfix

Postfix Greylisting - archives.neohapsis.com/archives/postfix/2003-07/1219.html
postgrey - postgrey.schweikert.ch/
Gld - www.gasmi.net/gld.html
gps – greylist policy service for postfix - mimo.gn.apc.org/gps/
policyd - www.policyd.org/ - C, mysql
SQLgrey - sqlgrey.sourceforge.net/ - perl
tumgreyspf - www.tummy.com/Community/software/tumgreyspf/
Gross - code.google.com/p/gross/

Greylisting for Exchange

JEP(S) - www.proxmea.com/JEPS
XWall - www.dataenter.co.at/products/xwall.htm

Greylisting SMTP Proxies

Spey: a greylisting SMTP proxy - spey.sourceforge.net/
smtpfilter.c - www.gtoal.com/spam/smtpfilter.c.html
Grappy - www.stacken.kth.se/~mattiasa/projects/grappy/
Fighting spam with pf - www.freebsddiary.org/pf.php
KamaeliaGrey - kamaelia.sourceforge.net/KamaeliaGrey

Other Greylisting Implementations

Denysoft Greylist - www.openfusion.com.au/labs/qpsmtpd/denysoft_greylist - plugin for QPSMTPd
Squirrelmail Greylist Plugin - toaster.godshell.com/index.php?n=Software.SquirrelmailGreylist - plugin for Squirrelmail
GLST - www.xmailserver.org/glst-mod.html
Gross - code.google.com/p/gross/ - supports Sun JMS as well as Postfix, Sendmail, Exim

Products Including Greylisting

Isode - www.isode.com/press/pr-antispam102.html
Canit - www.roaringpenguin.com/
YipeMail - www.yipemail.com/
DCC Greylists - www.rhyolite.com/anti-spam/dcc/greylist.html - DCC
Spamd - openbsd.org/spamd/
Tenbu - www.drcc.com/tenbu