Message Delivery Agent
A message delivery agent (MDA), or mail delivery agent, is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox., ''Internet Mail Architecture'', D. Crocker (July 2009) It is also called a local delivery agent (LDA). Within the Internet mail architecture, local message delivery is achieved through a process of handling messages from the message transfer agent, and storing mail into the recipient's environment (typically a mailbox). Implementation Many mail handling software products bundle multiple message delivery agents with the message transfer agent component, providing for site customization of the specifics of mail delivery to a user. Unix On Unix-like systems, procmail and maildrop are the most popular MDAs. The Local Mail Transfer Protocol (LMTP) is a protocol that is frequently implemented by network-aware MDAs. Invocation The mail delivery agent is generally not started from the command line, but ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU). Machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a particular storage location in the computer—an effect that is not directly observable to the user. An instruction may also invoke one of many input or output operations, for example displaying some text on a computer screen; causing state changes which should be visible to the user. The processor executes the instructions in the order they are provided, unless it is instructed ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Mail Retrieval Agent
A mail retrieval agent (MRA) is a computer application that retrieves or fetches e-mail from a remote mail server and works with a mail delivery agent to deliver mail to a local or remote email mailbox. MRAs may be external applications by themselves or be built into bigger applications like a mail user agent. Significant examples of standalone MRAs include fetchmail and getmail. The concept of an MRA is not standardized in email architecture. Although they operate like mail transfer agents, MRAs are technically clients when they retrieve and submit messages. Delivery mechanisms The mail retrieval agent may support delivery of retrieved mail via the following mechanisms: * Via a mail transport agent (Listening for SMTP transfers on port 25) * Via a mail delivery agent * Direct delivery to an mbox formatted mailbox * Direct delivery to a maildir directory * Output to standard output Multiple mailbox support The mail retriever agent may support retrieval of mail from multiple mailb ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Message User Agent
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email. A web application which provides message management, composition, and reception functions may act as a web email client, and a piece of computer hardware or software whose primary or most visible role is to work as an email client may also use the term. Retrieving messages from a mailbox Like most client programs, an email client is only active when a user runs it. The common arrangement is for an email user (the client) to make an arrangement with a remote Mail Transfer Agent (MTA) server for the receipt and storage of the client's emails. The MTA, using a suitable mail delivery agent (MDA), adds email messages to a client's storage as they arrive. The remote mail storage is referred to as the user's mailbox. The default setting on many Unix systems is for the mail server to store formatted messages in mbox, within the u ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Message Submission Agent
A message submission agent (MSA), or mail submission agent, is a computer program or software agent that receives electronic mail messages from a mail user agent (MUA) and cooperates with a mail transfer agent (MTA) for delivery of the mail. It uses ESMTP, a variant of the Simple Mail Transfer Protocol (SMTP), as specified in RFC 6409. Many MTAs perform the function of an MSA as well, but there are also programs that are specially designed as MSAs without full MTA functionality. Historically, in Internet mail, both MTA and MSA functions use port number 25, but the official port for MSAs is 587. The MTA accepts a user's incoming mail, while the MSA accepts a user's outgoing mail. Benefits Separation of the MTA and MSA functions produces several benefits. One benefit is that an MSA, since it is interacting directly with the author's MUA, can correct minor errors in a message's format (such as a missing ''Date'', ''Message-ID'', ''To'' fields, or an address with a missing domain ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Message Transfer Agent
Within the Internet email system, a message transfer agent (MTA), or mail transfer agent, or mail relay is software that transfers electronic mail messages from one computer to another using SMTP. The terms mail server, mail exchanger, and MX host are also used in some contexts. Messages exchanged across networks are passed between mail servers, including any attached data files (such as images, multimedia or documents). These servers also often keep mailboxes for email. Access to this email by end users is typically either via webmail or an email client. Operation A message transfer agent receives mail from either another MTA, a mail submission agent (MSA), or a mail user agent (MUA). The transmission details are specified by the Simple Mail Transfer Protocol (SMTP). When a recipient mailbox of a message is not hosted locally, the message is relayed, that is, forwarded to another MTA. Every time an MTA receives an email message, it adds a trace header field to the top of the he ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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GNU Mailutils
GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License (GPL). GNU is also the project within which the free software concept originated. Richard Stallman, the founder of the project, views GNU as a "technical means to a social end". Relatedly, Lawrence Lessig states in his introduction to the second edition of Stallman's book ''Free Software, Free Society'' that in it Stallman has written about "the social aspects of software and how Free Software can create community and social justice". Name ''GNU'' is a recursive acronym for "GNU's Not Unix!", chosen because GNU's design is Unix-like, but differs from Unix by being free software and containing no Unix code. Stallman chose th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Sieve (mail Filtering Language)
Sieve is a programming language that can be used for email filtering. It owes its creation to the CMU Cyrus Project, creators of Cyrus IMAP server. The language is not tied to any particular operating system or mail architecture. It requires the use of RFC-2822–compliant messages, but otherwise should generalize to other systems that meet these criteria. The current version of Sieve's base specification is outlined in RFC 5228, published in January 2008. Language Sieve is a data-driven programming language, similar to earlier email filtering languages such as procmail and maildrop, and earlier line-oriented languages such as sed and AWK: it specifies conditions to match and actions to take on matching. This differs from general-purpose programming languages in that it is highly limited – the base standard has no variables, and no loops (but does allow conditional branching), preventing runaway programs and limiting the language to simple filtering operations. Although extensio ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Sendmail
Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet. A descendant of the ''delivermail'' program written by Eric Allman, Sendmail is a well-known project of the free and open source software and Unix communities. It has spread both as free software and proprietary software. Overview Allman had written the original ARPANET delivermail which shipped in 1979 with 4.0 and 4.1 BSD. He wrote Sendmail as a derivative of delivermail in the early 1980s at UC Berkeley. It shipped with BSD 4.1c in 1983, the first BSD version that included TCP/IP protocols. In 1996, approximately 80% of the publicly reachable mail-servers on the Internet ran Sendmail. More recent surveys have suggested a decline, with 3.64% of mail servers in March 2021 detected as running Sendmail in a study performed by E-Soft, Inc. A previous survey ( ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Courier Mail Server
The Courier Mail Server is a mail transfer agent (MTA) server that provides SMTP, IMAP, POP3, SMAP, webmail, and mailing list services with individual components. It is best known for its IMAP server component. Courier can function as an intermediate mail relay, between an internal LAN and the Internet, or perform final delivery to mailboxes. Courier uses maildirs as its native storage format and can also deliver mail to legacy mailbox files. Configuration files are in plain text format and may include Perl scripts. Courier can provide mail services for regular operating system accounts. Courier can also provide mail services for virtual mail accounts, managed by any of LDAP directory service, Berkeley DB, MySQL or PostgreSQL authentication database. Parts of Courier, such as the maildrop filtering system, the webmail and IMAP server, can also be installed as independent packages which can be used with other mail servers. Courier-IMAP is a particularly popular combination with ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tmux
tmux is an open-source terminal multiplexer for Unix-like operating systems. It allows multiple terminal sessions to be accessed simultaneously in a single window. It is useful for running more than one command-line program at the same time. It can also be used to detach processes from their controlling terminals, allowing remote sessions to remain active without being visible. Features tmux includes most features of GNU Screen. It allows users to start a terminal session with clients that are not bound to a specific physical or virtual console; multiple terminal sessions can be created within a single terminal session and then freely rebound from one virtual console to another, and each session can have several connected clients. Some notable tmux features are: * Menus for interactive selection of running sessions, windows or clients * Window can be linked to an arbitrary number of sessions * vi-like or Emacs command mode (with auto completion) for managing tmux * Lack of ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Fdm (software)
fdm (fetch/filter and deliver mail) is a mail delivery agent and email filtering software for Unix-like operating systems, similar to fetchmail and procmail. It was started in 2006 by Nicholas Marriott who later also started tmux in 2007. Adoption fdm is available as a package in many Unix-like operating systems. It has been included in OpenBSD ports since 2007-01-18. When in 2014 the last maintainer of procmail posted a message to an OpenBSD mailing list himself suggesting that he remove the procmail port, it has been suggested by a well-known OpenBSD ports maintainer that fdm is the natural alternative (the procmail port, however, has not been removed and remains in place as of 2020). fdm is listed on the OpenBSD Innovations page, in the section of projects maintained by OpenBSD developers outside of OpenBSD. See also * fetchmail * procmail * maildrop * Sieve (mail filtering language) Sieve is a programming language that can be used for email filtering. It owes its ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Getmail
getmail is a simple mail retrieval agent intended as a replacement for fetchmail, implemented in Python. It can retrieve mail from POP3, IMAP4, and ''Standard Dial-up POP3 Service'' servers, with or without SSL. It supports simple and domain (multidrop) mailboxes, mail filtering via any arbitrary program, and supports a wide variety of mail destination types, including mboxrd, maildir, and external arbitrary mail delivery agents. Unlike fetchmail, getmail's Python foundation makes it nearly immune to buffer overflow security holes. It also has a simpler configuration syntax than fetchmail, but supports fewer authentication protocols. The software can also function as a basic mail delivery agent. Getmail is free software and is licensed under the GNU General Public License version 2. It is written and maintained by Charles Cazabon. The original getmail software requires Python 2, which is no longer supported. A fork named getmail6, which is not from getmail's original author ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |