Electronic mail is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail. Email is a ubiquitous and very widely used communication medium; 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.
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 the Simple Mail Transfer Protocol. In some contexts the alternative names mail server, mail exchanger, and MX host can be used to describe an MTA.
The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per RFC 8314. For retrieving messages, IMAP is standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.
Webmail is an email service that can be accessed using a standard web browser. It contrasts with email service accessible through a specialised email client software. Examples of webmail providers are AOL Mail, Proton Mail, Gmail, GMX Mail, Mailfence, Outlook.com/Hotmail.com, and Yahoo! Mail. Additionally, many internet service providers (ISP) provide webmail as part of their internet service package. Similarly, some web hosting providers also provide webmail as a part of their hosting package.
Eudora is an email client that was used on the classic Mac OS, Mac OS X, and Microsoft Windows operating systems. It also supported several palmtop computing platforms, including Newton and the Palm OS. In 2018, after being years out of print, the software was open-sourced by the Computer History Museum.
Various anti-spam techniques are used to prevent email spam.
Pegasus Mail is a proprietary email client developed by David Harris. It was originally released in 1990 for internal and external mail on NetWare networks with MS-DOS and later Apple Macintosh clients. It was subsequently ported to Microsoft Windows, which is now the only platform actively supported. Previously freeware, Pegasus Mail is now donationware.
Greylisting is a method of defending e-mail users against spam. A mail transfer agent (MTA) using greylisting will "temporarily reject" any email from a sender it does not recognize. If the mail is legitimate, the originating server will try again after a delay, and if sufficient time has elapsed, the email will be accepted.
The following tables compare general and technical features of notable email client programs.
Mercury Mail Transport System is a standards-compliant mail server developed by David Harris, who also develops the Pegasus Mail client.
Zimbra Collaboration, formerly known as the Zimbra Collaboration Suite (ZCS) before 2019, is a collaborative software suite that includes an email server and a web client.
The following tables compare general and technical information for a number of notable webmail providers who offer a web interface in English.
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.
GMX Mail is a free advertising-supported email service provided by GMX. Users may access received GMX Mail via webmail, or using POP3 or IMAP4 protocols. Mail is sent using SMTP. Founded in 1997, GMX is a subsidiary of United Internet AG, a stock-listed company in Germany, and a sister company to 1&1 Internet and Fasthosts Internet. In addition to an email address, each GMX account includes a Mail Collector, Address Book, Organizer, and File Storage. Every user can register up to 10 individual GMX email addresses. Popup ads are displayed to all users, including premium, at GMX login; as of 2021 GMX was the only large email provider using popup ads.
Zarafa was an open-source groupware application that originated in the city of Delft in the Netherlands. The company that developed Zarafa, previously known as Connectux, is also called Zarafa. The Zarafa groupware provided email storage on the server side and offered its own Ajax-based mail client called WebAccess and a HTML5-based, WebApp. Advanced features were available in commercially supported versions. Zarafa has been superseded by Kopano.
Ipswitch IMail Server is an email server application with groupware functionality that runs on Microsoft Windows OS. It was developed in 1994 by Ipswitch, Inc., a software company based in Lexington, Massachusetts.
EmailTray is a lightweight email client for the Microsoft Windows operating system. EmailTray was developed by Internet Promotion Agency S.A., a software development d.
A mailbox provider, mail service provider or, somewhat improperly, email service provider is a provider of email hosting. It implements email servers to send, receive, accept, and store email for other organizations or end users, on their behalf.
MailSite is a commercial mail server, calendar software, contact manager and collaborative software that was developed by Rockliffe Systems. It was one of the first mail servers to run on Windows NT using Internet standards when version 1.2 was released in 1996. Additionally, MailSite has been in continual development since 1996 with version 10 released in 2013, and runs on a single Windows Server as well as on a cluster of Windows Server computers. MailSite works natively with Microsoft Outlook versions 2007 to 2013 for mail, calendar and contacts without requiring any Outlook plug-ins, as well as including an Exchange ActiveSync (EAS) server for synchronizing mail, calendar and contacts with mobile devices. MailSite also works with Internet Standards-based mail clients such as Mozilla Thunderbird.
MailEnable is a Windows-based, commercial email server distributed by MailEnable Pty. Ltd, an Australian-based software company which was established in 2002.
