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18-405: Eudora Internet Mail Server (EIMS) is a POP3 , IMAP , and SMTP server for the classic Mac OS and macOS . In 1993 Glenn Anderson started development on what was then called MailShare, which was available as freeware. In 1995 MailShare was purchased by Apple Computer and renamed to Apple Internet Mail Server. Version 1.0 to 1.2 were released under that name. In 1997 Apple Internet Mail Server

36-473: A Kerberized version. RFC 1460 introduced APOP into the core protocol. APOP is a challenge–response protocol which uses the MD5 hash function in an attempt to avoid replay attacks and disclosure of the shared secret . Clients implementing APOP include Mozilla Thunderbird , Opera Mail , Eudora , KMail , Novell Evolution , RimArts' Becky! , Windows Live Mail , PowerMail, Apple Mail , and Mutt . RFC 1460

54-426: A facility allowing one user to assume the identity of another. They can also provide a data security layer offering data integrity and data confidentiality services. DIGEST-MD5 provides an example of mechanisms which can provide a data-security layer. Application protocols that support SASL typically also support Transport Layer Security (TLS) to complement the services offered by SASL. John Gardiner Myers wrote

72-498: A licence), suggesting that the project might have become abandoned. The server software also handles the ACAP and LDAP services. POP3 The Post Office Protocol provides access via an Internet Protocol (IP) network for a user client application to a mailbox ( maildrop ) maintained on a mail server. The protocol supports list, retrieve and delete operations for messages. POP3 clients connect, retrieve all messages, store them on

90-530: A unique identifier assigned to the message by the POP server. This unique identifier is permanent and unique to the maildrop and allows a client to access the same message in different POP sessions. Mail is retrieved and marked for deletion by the message-number. When the client exits the session, mail marked for deletion is removed from the maildrop. The first version of the Post Office Protocol, POP1,

108-878: Is an example in RFC 1939: POP3 servers without the optional APOP command expect the client to log in with the USER and PASS commands: The Internet Message Access Protocol (IMAP) is an alternative and more recent mailbox access protocol. The highlights of differences are: Simple Authentication and Security Layer Simple Authentication and Security Layer ( SASL ) is a framework for authentication and data security in Internet protocols . It decouples authentication mechanisms from application protocols , in theory allowing any authentication mechanism supported by SASL to be used in any application protocol that uses SASL. Authentication mechanisms can also support proxy authorization ,

126-458: Is either requested after protocol initiation, using the STLS command, if supported, or by POP3S, which connects to the server using Transport Layer Security (TLS) or Secure Sockets Layer (SSL) on well-known TCP port number 995. Messages available to the client are determined when a POP3 session opens the maildrop, and are identified by message-number local to that session or, optionally, by

144-650: The Kerberized Post Office Protocol ( KPOP ), an application-layer Internet standard protocol , to retrieve e-mail from a remote server over a TCP/IP connection. The KPOP protocol is based on the POP3 protocol – differing in that it adds Kerberos security and that it runs by default over TCP port number 1109 instead of 110. One mail server software implementation is found in the Cyrus IMAP server . The following POP3 session dialog

162-510: The CAPA command. With the exception of APOP, the optional commands were included in the initial set of capabilities. Following the lead of ESMTP (RFC 5321), capabilities beginning with an X signify local capabilities. The STARTTLS extension allows the use of Transport Layer Security (TLS) or Secure Sockets Layer (SSL) to be negotiated using the STLS command, on the standard POP3 port, rather than an alternate. Some clients and servers instead use

180-548: The UIDL command (unique-id list). By contrast, the Internet Message Access Protocol (IMAP) was designed to normally leave all messages on the server to permit management with multiple client applications, and to support both connected ( online ) and disconnected ( offline ) modes of operation. A POP3 server listens on well-known port number 110 for service requests. Encrypted communication for POP3

198-399: The alternate-port method, which uses TCP port 995 (POP3S). Demon Internet introduced extensions to POP3 that allow multiple accounts per domain, and has become known as Standard Dial-up POP3 Service (SDPS). To access each account, the username includes the hostname, as john@hostname or john+hostname . Google Apps uses the same method. In computing , local e-mail clients can use

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216-516: The client computer, and finally delete them from the server. This design of POP and its procedures was driven by the need of users having only temporary Internet connections, such as dial-up access , allowing these users to retrieve e-mail when connected, and subsequently to view and manipulate the retrieved messages when offline. POP3 clients also have an option to leave mail on the server after retrieval, and in this mode of operation, clients will only download new messages which are identified by using

234-485: The original POP3 specification supported only an unencrypted USER/ PASS login mechanism or Berkeley .rhosts access control, today POP3 supports several authentication methods to provide varying levels of protection against illegitimate access to a user's e-mail. Most are provided by the POP3 extension mechanisms. POP3 clients support SASL authentication methods via the AUTH extension. MIT Project Athena also produced

252-440: The original SASL specification (RFC 2222) in 1997. In 2006, that document was replaced by RFC 4422 authored by Alexey Melnikov and Kurt D. Zeilenga. SASL, as defined by RFC 4422 is an IETF Standard Track protocol and is, as of 2006 , a Proposed Standard . A SASL mechanism implements a series of challenges and responses. Defined SASL mechanisms include: Application protocols define their representation of SASL exchanges with

270-458: The other POP4 server implementation. An extension mechanism was proposed in RFC 2449 to accommodate general extensions as well as announce in an organized manner support for optional commands, such as TOP and UIDL. The RFC did not intend to encourage extensions, and reaffirmed that the role of POP3 is to provide simple support for mainly download-and-delete requirements of mailbox handling. The extensions are termed capabilities and are listed by

288-484: Was obsoleted by RFC 1725, which was in turn obsoleted by RFC 1939. POP4 exists only as an informal proposal adding basic folder management, multipart message support, as well as message flag management to compete with IMAP; however, its development has not progressed since 2003.There are now two known POP4 server implementations. As of October 2013, the POP4.org domain and website are now hosted by simbey.com, which also runs

306-461: Was purchased by Qualcomm and renamed to Eudora Internet Mail Server. Version 1.3 was released as freeware by Qualcomm. Versions 2.0 to 3.0 were released by Qualcomm as a commercial product. In 2001 Qualcomm licensed EIMS back to Glenn Anderson, who has released versions 3.1, 3.2 and 3.3. As of April 2024, the latest version is 3.3.10 of 30 Oct 2022, and the payment processor is Kagi that went out of business on 31 July 2016 (making it impossible to buy

324-417: Was specified in RFC 918 (1984) by Joyce K. Reynolds . POP2 was specified in RFC 937 (1985). POP3 is the version in most common use. It originated with RFC 1081 (1988) but the most recent specification is RFC 1939, updated with an extension mechanism (RFC 2449) and an authentication mechanism in RFC 1734. This led to a number of POP implementations such as Pine, POPmail , and other early mail clients. While

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