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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, 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNSBL
A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query whether a sending host's IP address is blacklisted for email spam. Most mail server software can be configured to check such lists, typically rejecting or flagging messages from such sites. A DNSBL is a software mechanism, rather than a specific list or policy. Dozens of DNSBLs exist. They use a wide array of criteria for listing and delisting addresses. These may include listing the addresses of zombie computers or other machines being used to send spam, Internet service providers (ISPs) who willingly host spammers, or those which have sent spam to a honeypot system. Since the creation of the first DNSBL in 1998, the operation and policies of these lists have frequently been controversial, both in Internet advocacy circles and occasionally ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milter
Milter ( portmanteau for ''mail filter'') is an extension to the widely used open source mail transfer agents (MTA) Sendmail and Postfix. It allows administrators to add mail filters for filtering spam or viruses in the mail-processing chain. In the language of the art, "milter" refers to the protocol and API implementing the service, while "a milter" has come to refer to a filter application that uses milter to provide service. History Prior to the advent of milter, an email filter was generally implemented as a program to which an MTA would hand the message once it has completely arrived, with most of the message's envelope information removed. That program could then analyze the header and body of the message and make a decision to accept the message (i.e. return a "success" status to the MTA) or reject it (i.e. return a "failed" status to the MTA). The MTA would then log a successful delivery or return a failure message to the sender as appropriate, and the filter would ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIME
Multipurpose Internet Mail Extensions (MIME) is an Internet standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs. Message bodies may consist of multiple parts, and header information may be specified in non-ASCII character sets. Email messages with MIME formatting are typically transmitted with standard protocols, such as the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol (POP), and the Internet Message Access Protocol (IMAP). The MIME standard is specified in a series of requests for comments: , , , , and . The integration with SMTP email is specified in and . Although the MIME formalism was designed mainly for SMTP, its content types are also important in other communication protocols. In the HyperText Transfer Protocol (HTTP) for the World Wide Web, servers insert a MIME header field at the beginning of any Web transmission. Clien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regular Expression
A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation. Regular expression techniques are developed in theoretical computer science and formal language theory. The concept of regular expressions began in the 1950s, when the American mathematician Stephen Cole Kleene formalized the concept of a regular language. They came into common use with Unix text-processing utilities. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in search engines, in search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK, and in lexical analysis. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipe (computing)
The vertical bar, , is a glyph with various uses in mathematics, computing, and typography. It has many names, often related to particular meanings: Sheffer stroke (in logic), pipe, bar, or (literally the word "or"), vbar, and others. Usage Mathematics The vertical bar is used as a mathematical symbol in numerous ways: * absolute value: , x, , read "the ''absolute value'' of ''x''" * cardinality: , S, , read "the ''cardinality'' of the set ''S''" * conditional probability: P(X, Y), reads "the probability of ''X'' ''given'' ''Y''" * determinant: , A, , read "the ''determinant'' of the matrix ''A''". When the matrix entries are written out, the determinant is denoted by surrounding the matrix entries by vertical bars instead of the usual brackets or parentheses of the matrix, as in \begin a & b \\ c & d\end. * distance: P, ab, denoting the shortest ''distance'' between point P to line ab, so line P, ab is perpendicular to line ab * divisibility: a \mid b, read "''a'' ''divide ... [...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] |
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 emplo ... [...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 ar ... [...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 that u ... [...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 forma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIMEDefang
MIMEDefang is a GNU General Public License, GPL software license, licensed framework for e-mail filtering, filtering e-mail. It uses sendmail's "Milter" API, some C (programming language), C glue code, and some Perl code to let the user write high-performance mail filters in Perl. MIMEDefang can be used to: * Block Computer virus, viruses (e.g. using Clamav) * Block or tag E-mail spam, spam (e.g. using SpamAssassin) * Remove HTML mail parts * Add boilerplate disclaimers to outgoing mail * Remove or alter Email attachment, 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 computer network, network. The software was written to filter attachments and was originally called MIMESweeper, then MIMEDefanger, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
