Electronic mail is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic (digital) version of, or counterpart to, mail, at a time when "mail" meant only physical mail. Email later became a ubiquitous communication medium, to the point that in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.
Spamming is the use of messaging systems to send multiple unsolicited messages (spam) to large numbers of recipients for the purpose of commercial advertising, for the purpose of non-commercial proselytizing, for any prohibited purpose, or simply repeatedly sending the same message to the same user. While the most widely recognized form of spam is email spam, the term is applied to similar abuses in other media: instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, wiki spam, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social spam, spam mobile apps, television advertising and file sharing spam. It is named after Spam, a luncheon meat, by way of a Monty Python sketch about a restaurant that has Spam in almost every dish in which Vikings annoyingly sing "Spam" repeatedly.
Apache SpamAssassin is a computer program used for e-mail spam filtering. It uses a variety of spam-detection techniques, including DNS and fuzzy checksum techniques, Bayesian filtering, external programs, blacklists and online databases. It is released under the Apache License 2.0 and is a part of the Apache Foundation since 2004.
GNU Mailman is a computer software application from the GNU Project for managing electronic mailing lists. Mailman is coded primarily in Python and currently maintained by Abhilash Raj. Mailman is free software, licensed under the GNU General Public License.
Various anti-spam techniques are used to prevent email spam.
Email spam, also referred to as junk email, spam mail, or simply spam, is unsolicited messages sent in bulk by email (spamming).
A Joe job is a spamming technique that sends out unsolicited e-mails using spoofed sender data. Early Joe jobs aimed at tarnishing the reputation of the apparent sender or inducing the recipients to take action against them, but they are now typically used by commercial spammers to conceal the true origin of their messages and to trick recipients into opening emails apparently coming from a trusted source.
Clam AntiVirus (ClamAV) is a free software, cross-platform antimalware toolkit able to detect many types of malware, including viruses. It was developed for Unix and has third party versions available for AIX, BSD, HP-UX, Linux, macOS, OpenVMS, OSF (Tru64) and Solaris. As of version 0.97.5, ClamAV builds and runs on Microsoft Windows. Both ClamAV and its updates are made available free of charge. One of its main uses is on mail servers as a server-side email virus scanner.
Sender ID is an historic 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 4406, but there are additional parts in RFC 4405, RFC 4407 and RFC 4408.
Norton AntiVirus is an anti-virus or anti-malware software product founded by Peter Norton, developed and distributed by Gen Digital since 1991 as part of its Norton family of computer security products. It uses signatures and heuristics to identify viruses. Other features included in it are e-mail spam filtering and phishing protection.
Norton Internet Security, developed by Symantec Corporation, is a discontinued computer program that provides malware protection and removal during a subscription period. It uses signatures and heuristics to identify viruses. Other features include a personal firewall, email spam filtering, and phishing protection. With the release of the 2015 line in summer 2014, Symantec officially retired Norton Internet Security after 14 years as the chief Norton product. It was superseded by Norton Security, a rechristened adaptation of the Norton 360 security suite.
Email harvesting or scraping is the process of obtaining lists of email addresses using various methods. Typically these are then used for bulk email or spam.
SORBS is a list of e-mail servers suspected of sending or relaying spam. It has been augmented with complementary lists that include various other classes of hosts, allowing for customized email rejection by its users.
Defensive computing is a form of practice for computer users to help reduce the risk of computing problems, by avoiding dangerous computing practices. The primary goal of this method of computing is to be able to anticipate and prepare for potentially problematic situations prior to their occurrence, despite any adverse conditions of a computer system or any mistakes made by other users. This can be achieved through adherence to a variety of general guidelines, as well as the practice of specific computing techniques.
MIMEDefang is a GPL licensed framework for filtering e-mail. It uses sendmail's "Milter" API, some C glue code, and some Perl code to let the user write high-performance mail filters in Perl.
Kaspersky Internet Security is an internet security suite developed by Kaspersky Lab compatible with Microsoft Windows and Mac OS X. Kaspersky Internet Security offers protection from malware, as well as email spam, phishing and hacking attempts, and data leaks. Kaspersky Lab Diagnostics results are distributed to relevant developers through the MIT License.
hMailServer is a free email server for Windows created by Martin Knafve. It runs as a Windows service and includes administration tools for management and backup. It has support for IMAP, POP3, and SMTP email protocols. It can use external database engines such as MySQL, MS SQL or PostgreSQL, or an internal MS SQL Compact Edition engine to store configuration and index data. The actual email messages are stored on disk in a raw MIME format. It has active support and development forums.
People tend to be much less bothered by spam slipping through filters into their mail box, than having desired e-mail ("ham") blocked. Trying to balance false negatives vs false positives is critical for a successful anti-spam system. As servers are not able to block all spam there are some tools for individual users to help control over this balance.
SmartScreen is a cloud-based anti-phishing and anti-malware component included in several Microsoft products, including operating systems Windows 8 and later, the applications Internet Explorer, Microsoft Edge. SmartScreen intelligence is also used in the backend of Microsoft's online services such as the web app Outlook.com and Microsoft Bing search engine.
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 provide protection against spam and viruses and other malware. It can be considered an interface between a mailer and one or more content filters.
