Akismet Akismet or Automattic Kismet is a spam filtering service.
Amavis Amavis is an open source content filter for electronic mail, implementing mail message transfer, decoding, some processing and checking, and interfacing with external content filters to prov...
Anti-spam appliances Anti-spam appliances are hardware devices integrated with on-board software that implement anti-spam techniques and/or anti-spam for instant messaging and are deployed at the gateway or in front...
Anti-Spam SMTP Proxy The Anti-Spam SMTP Proxy server project is an Open Source, Perl based, platform-independent transparent SMTP proxy server available at SourceForge.net that leverages numerous methodologies and t...
Anti-spam techniques Unsolicited bulk email), both end users and administrators of email systems use various anti-spam techniques.
Bogofilter Bogofilter is a mail filter that classifies e-mail as spam or ham (non-spam) by a statistical analysis of the message's header and content (body).
Boxbe Boxbe is a free service that purports to screen spam in personal email.
Callback verification Callback verification, also known as callout verification or Sender Address Verification, is a technique used by SMTP software in order to validate e-mail addresses.
Challenge-response spam filtering A challenge–response (or C/R) system is a type of spam filter that automatically sends a reply with a challenge to the (alleged) sender of an incoming e-mail.
Cloudmark Cloudmark, Inc is a privately held company, San Francisco-based, providing protection against spam, viruses, phishing, and similar threats that affect email.
Complement set email filtering Complement Set Filtering (CSF) is a method for filtering unsolicited bulk email (UBE or spam) The technique utilizes at least two email accounts: the primary account where spam and non-spam is r...
Content filtering Content filtering is the technique whereby content is blocked or allowed based on analysis of its content, rather than its source or other criteria.
Context filtering Context filtering is an anti-spam / mail policy method that does not deal with the contents of the mail but rather uses the context of the SMTP connection to decide whether a mail will be accept...
DMARC In telephony, the demarcation point is the point at which the telephone company network ends and connects with the wiring at the customer premises.
DNSBL A DNS-based Blackhole List (DNSBL) or Real-time Blackhole List (RBL) is a list of IP addresses published through the Internet Domain Name System (DNS) either as a zone file that can be use...
DNSWL DNSWL (DNS-based whitelist) is both a generic term and a specific list.
DomainKeys DomainKeys is an e-mail authentication system designed to verify the DNS domain of an e-mail sender and the message integrity.
DomainKeys Identified Mail DomainKeys Identified Mail (DKIM) is a method for associating a domain name with an email message, thereby allowing a person, role, or organization to claim some responsibility for the message.
DSPAM DSPAM is a free software statistical spam filter written by Jonathan A. Zdziarski, author of the book Ending Spam (ISBN 1593270526) and other books.
E-mail filtering Email filtering is the processing of email to organize it according to specified criteria.
Email filtering Email filtering is the processing of email to organize it according to specified criteria.
Exchange Online Protection Exchange Online Protection (EOP, formerly Forefront Online Protection for Exchange or FOPE) is a hosted e-mail security service, owned by Microsoft, that filters spam and remov...
Greylisting Greylisting is a method of defending e-mail users against spam.
Guinevere (software) Guinevere is an e-mail filtering program that is built for use with the GroupWise e-mail system.
Hashcash Hashcash is a proof-of-work system designed to limit email spam and denial-of-service attacks.
Hexamail Guard Hexamail Guard is a server based software antispam filter for the Windows and Linux platforms.
MailChannels MailChannels is a privately held, anti-spam technology company based in Vancouver, British Columbia.
MailScanner MailScanner is an open source e-mail security system for use on Unix e-mail gateways and was first released in 2001.
Mailwasher Mailwasher is an e-mail filtering software for Windows, Unix, and Macintosh systems that can detect and delete spam from a user's e-mail when it is on the mail server, before being downloaded to...
MARID MARID was an IETF working group in the applications area tasked to propose standards for E-mail authentication in 2004.
Markovian discrimination Markovian discrimination in spam filtering is a method used in CRM114 and other spam filters to model the statistical behaviors of spam and nonspam more accurately than in simple Bayesian methods.
Messaging Architects Messaging Architects (MA) is a Canadian software company specializing in e-mail products.
MIMEDefang MIMEDefang is a GPL licensed framework for filtering e-mail.
Mollom Mollom is a web service that analyzes the quality of content posted to websites.
Nolisting Nolisting is a method of defending electronic mail users against e-mail spam.
OCML Open Configuration and Management Layer (OCML) is a universal application configuration and management layer that helps to develop integrated applications independent of underlying group o...
Penny Black (research project) The Penny Black Project is a Microsoft Research project that tries to find effective and practical ways of fighting spam.
Policyd-weight policyd-weight is a mail filter for the Postfix mail transfer agent (MTA) written in Perl, by Robert Felber.
POPFile POPFile is a free, open source, cross-platform mail filter originally written in Perl by John Graham-Cumming and maintained by a team of volunteers.
Postini Postini is an e-mail, Web security, and archiving service owned by Google since 2007.
Proofpoint, Inc. Proofpoint, Inc. is based in Sunnyvale, California and provides SaaS and on-premises solutions for inbound email security, outbound data loss prevention, privacy protection, email encryption, el...
Red Condor Red Condor, Inc. is a privately held company that offers anti-spam appliances and a hosted service that block e-mail spam, spyware, and viruses.
Scunthorpe problem The Scunthorpe problem is the blocking of e-mails, forum posts or search results by a spam filter or search engine because their text contains a string of letters that are shared with an obscen...
Sender ID Sender ID is an anti-spoofing proposal from the former MARID IETF working group that tried to join Sender Policy Framework (SPF) and Caller ID. Sender ID is defined primarily in Experimental RFC...
Sender Policy Framework Sender Policy Framework (SPF) is an email validation system designed to prevent email spam by detecting email spoofing, a common vulnerability, by verifying sender IP addresses.
Sendio Sendio is an Irvine, California-based e-mail security company.
SMTP proxy SMTP proxies are specialized Mail Transfer Agents (MTAs) that, similar to other types of proxy servers, pass SMTP sessions through to other MTAs without using the store-and-forward approach of a...
Spam Bully Spam Bully is anti-spam software made by Axaware, LLC. SpamBully uses Bayesian filtering to separate good emails from spam emails.
Spam Reader Spam Reader is a anti-spam add-on for Microsoft Outlook, produced under shareware license.
SpamAssassin SpamAssassin is a computer program released under the Apache License 2.0 used for e-mail spam filtering based on content-matching rules.
SpamBayes SpamBayes is a Bayesian spam filter written in Python which uses techniques laid out by Paul Graham in his essay "A Plan for Spam".
SPAMfighter SPAMfighter is an antispam software product and also the name of the company which produces it.
Sparse binary polynomial hashing Sparse binary polynomial hashing (SBPH) is a generalization of Bayesian filtering that can match mutating phrases as well as single words.
Tagged Message Delivery Agent TMDA is an open-source software application designed to reduce the amount of spam (Internet junk-mail) a user receives.
The Abusive Hosts Blocking List The Abusive Hosts Blocking List is an internet abuse tracking and filtering system developed by The Summit Open Source Development Group, and based on the original Summit Blocking List (2000–2002).
Trusted Email Open Standard The Trusted Email Open Standard (TEOS) is an anti-spam technique proposed by the ePrivacy Group in 2003 at the Federal Trade Commission Anti-Spam Summit.