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SpamAssassin
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. The program can be integrated with the mail server to automatically filter all mail for a site. It can also be run by individual users on their own mailbox and integrates with several mail programs. Apache SpamAssassin is highly configurable; if used as a system-wide filter it can still be configured to support per-user preferences. History Apache SpamAssassin was created by Justin Mason, who had maintained a number of patches against an earlier program named ''filter.plx'' by Mark Jeftovic, which in turn was begun in August 1997. Mason rewrote all of Jeftovic's code from scratch and uploaded the resulting codebase to SourceForge on April 20, 2001. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 provide protection against spam and viruses and other malware. It can be considered an interface between a mailer ( MTA, Mail Transfer Agent) and one or more content filters. ''Amavis'' can be used to: * detect viruses, spam, banned content types or syntax errors in mail messages * block, tag, redirect (using sub-addressing), or forward mail depending on its content, origin or size * quarantine (and release), or archive mail messages to files, to mailboxes, or to a relational database * sanitize passed messages using an external sanitizer * generate DKIM signatures * verify DKIM signatures and provide DKIM-based whitelisting Notable features: * provides SNMP statistics and status monitoring using an extensive MIB with more than 300 variables * provides structured event log in JSON format * I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayesian Spam Filtering
Naive Bayes classifiers are a popular statistical technique of e-mail filtering. They typically use bag-of-words features to identify email spam, an approach commonly used in text classification. Naive Bayes classifiers work by correlating the use of tokens (typically words, or sometimes other things), with spam and non-spam e-mails and then using Bayes' theorem to calculate a probability that an email is or is not spam. Naive Bayes spam filtering is a baseline technique for dealing with spam that can tailor itself to the email needs of individual users and give low false positive spam detection rates that are generally acceptable to users. It is one of the oldest ways of doing spam filtering, with roots in the 1990s. History Bayesian algorithms were used for email filtering as early as 1996. Although naive Bayesian filters did not become popular until later, multiple programs were released in 1998 to address the growing problem of unwanted email. The first scholarly publicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIMEDefang
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. MIMEDefang can be used to: * Block viruses (e.g. using Clamav) * Block or tag spam (e.g. using SpamAssassin) * Remove HTML mail parts * Add boilerplate disclaimers to outgoing mail * Remove or alter attachments * Replace attachments with URLs * Implement sophisticated access controls * Verify and add DKIM and ARC signatures History MIMEDefang was originally developed by Dianne Skoll, who was contracted by the Royal College of Physicians and Surgeons of Canada in 2000 to help stop the flood of email viruses to the college's network. The software was written to filter attachments and was originally called MIMESweeper, then MIMEDefanger, and currently MIMEDefang. Skoll announced her software to the public on August 28, 2000. On December 21, 2001, a version incorporating support for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-spam Techniques
Various anti-spam techniques are used to prevent email spam (unsolicited bulk email). No technique is a complete solution to the spam problem, and each has trade-offs between incorrectly rejecting legitimate email ( false positives) as opposed to not rejecting all spam email ( false negatives) – and the associated costs in time, effort, and cost of wrongfully obstructing good mail. Anti-spam techniques can be broken into four broad categories: those that require actions by individuals, those that can be automated by email administrators, those that can be automated by email senders and those employed by researchers and law enforcement officials. End-user techniques There are a number of techniques that individuals can use to restrict the availability of their email addresses, with the goal of reducing their chance of receiving spam. Discretion Sharing an email address only among a limited group of correspondents is one way to limit the chance that the address will be "harve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procmail
procmail is an email server software component — specifically, a message delivery agent (MDA). It was one of the earliest mail filter programs. It is typically used in Unix-like mail systems, using the mbox and Maildir storage formats. procmail was first developed in 1990, by Stephen R. van den Berg. Philip Guenther took over maintainership for a number of years, but relinquished the role in 2014. The software remained unmaintained for several years, and was believed to be defunct. In 2020 May, Stephen van den Berg resumed maintenance again. The program has since seen multiple releases and bug-fixes. Uses The most common use case for procmail is filter mail into different mailboxes, based on criteria such as sender address, subject keywords, and/or mailing list address. Another use is to let procmail call an external spam filter program, such as SpamAssassin. This method can allow for spam to be filtered or deleted. The procmail developers have built a mailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MailScanner
MailScanner is an open source email security system for use on Unix email gateways and was first released in 2001. It protects against viruses, spam, malware, and phishing. It is distributed under the GNU General Public License. The original author, Julian Field, won the 2004 Open Source Award from UKUUG for the product. Worldwide, the software is estimated to be process over eighty billion emails per month, with millions of downloads. ISPs and mobile telephone networks are included in this list of users. More recently, anti-phishing measures have been introduced. The software spots attempts at obfuscating URLs (for example, to lure the user into thinking they are signing into their bank, when in reality they are using an impostor web site) and modifies the email with a suitable warning. As of January 2014 the project is sponsored by the lead developer Jerry Benton who is the founder oMailborder Systems As of January 2018 the primary developer is Shawn Iverson of theFa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuzzy Checksum
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data integrity but are not relied upon to verify data authenticity. The procedure which generates this checksum is called a checksum function or checksum algorithm. Depending on its design goals, a good checksum algorithm usually outputs a significantly different value, even for small changes made to the input. This is especially true of cryptographic hash functions, which may be used to detect many data corruption errors and verify overall data integrity; if the computed checksum for the current data input matches the stored value of a previously computed checksum, there is a very high probability the data has not been accidentally altered or corrupted. Checksum functions are related to hash functions, fingerprints, randomization functions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Client (computing)
In computing, a client is a piece of computer hardware or software that accesses a service made available by a server as part of the client–server model of computer networks. The server is often (but not always) on another computer system, in which case the client accesses the service by way of a network. A client is a computer or a program that, as part of its operation, relies on sending a request to another program or a computer hardware or software that accesses a service made available by a server (which may or may not be located on another computer). For example, web browsers are clients that connect to web servers and retrieve web pages for display. Email clients retrieve email from mail servers. Online chat uses a variety of clients, which vary on the chat protocol being used. Multiplayer video games or online video games may run as a client on each computer. The term "client" may also be applied to computers or devices that run the client software or users t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daemon (computer Software)
In multitasking computer operating systems, a daemon ( or ) is a computer program that runs as a background process, rather than being under the direct control of an interactive user. Traditionally, the process names of a daemon end with the letter ''d'', for clarification that the process is in fact a daemon, and for differentiation between a daemon and a normal computer program. For example, is a daemon that implements system logging facility, and is a daemon that serves incoming SSH connections. In a Unix environment, the parent process of a daemon is often, but not always, the init process. A daemon is usually created either by a process forking a child process and then immediately exiting, thus causing init to adopt the child process, or by the init process directly launching the daemon. In addition, a daemon launched by forking and exiting typically must perform other operations, such as dissociating the process from any controlling terminal (tty). Such procedures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache Software Foundation
The Apache Software Foundation (ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open source software projects. The ASF was formed from a group of developers of the Apache HTTP Server, and incorporated on March 25, 1999. As of 2021, it includes approximately 1000 members. The Apache Software Foundation is a decentralized open source community of developers. The software they produce is distributed under the terms of the Apache License and is a non-copyleft form of free and open-source software (FOSS). The Apache projects are characterized by a collaborative, consensus-based development process and an open and pragmatic software license, which is to say that it allows developers who receive the software freely, to re-distribute it under nonfree terms. Each project is managed by a self-selected team of technical experts who are active contributors to the project. The ASF is a meritocracy, implying tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mail Filter
Email filtering is the processing of email to organize it according to specified criteria. The term can apply to the intervention of human intelligence, but most often refers to the automatic processing of messages at an SMTP server, possibly applying anti-spam techniques. Filtering can be applied to incoming emails as well as to outgoing ones. Depending on the calling environment, email filtering software can reject an item at the initial SMTP connection stage or pass it through unchanged for delivery to the user's mailbox. It is also possible to redirect the message for delivery elsewhere, quarantine it for further checking, modify it or 'tag' it in any other way. Motivation Common uses for mail filters include organizing incoming email and removal of spam and computer viruses. Mailbox providers filter outgoing email to promptly react to spam surges that may result from compromised accounts. A less common use is to inspect outgoing email at some companies to ensure that empl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
