Method of authentication used by mail server software
POP before SMTP or SMTP after POP is a method of authentication used by mail server software which helps allow users the option to send e-mail from any location, as long as they can demonstrably also fetch their mail from the same place.
The POP before SMTP approach has been superseded by SMTP Authentication.
Technically, users are allowed to use SMTP from an IP address as long as they have previously made a successful login into the POP service at the same mail hosting provider, from the same address, within a predefined timeout period.
The main advantage of this process is that it was generally transparent to the average user who will be connecting with an email client, which almost always attempted to fetch new mail before sending new mail. The disadvantages include a potentially complex setup for the mail hosting provider (requiring some sort of communication channel between the POP service and the SMTP service) and uncertainty as to how much time users will take to connect via SMTP (to send mail) after connecting to POP.
Those users not handled by this method need to resort to other authorization methods. Also, in cases where users come from externally controlled dynamically assigned addresses, the SMTP server must be careful about not giving too much leeway when allowing unauthorized connections, because of a possibility of race conditions leaving an open mail relay unintentionally exposed.
POPbeforeSMTP or SMTP after POP is a method of authentication used by mail server software which helps allow users the option to send e-mail from any...
Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send...
or else using specific hacks, such as POPbeforeSMTP. John Gardiner Myers published the first draft of SMTP AUTH in 1995, and it has been successively...
SMTPS (Simple Mail Transfer Protocol Secure) is a method for securing the SMTP using transport layer security. It is intended to provide authentication...
to allow remote users to send mail. These include smart hosts, SMTP-AUTH, POPbeforeSMTP, and the use of virtual private networks (VPNs). The Internet...
as described in SMTP-AUTH (ESMTPA), or by other means such as RADIUS, public key certificates, or (the mostly obsolete) POPbeforeSMTP. The MSA must check...
typically either an MSA or an MTA, two variations of the SMTP protocol. The email client which uses the SMTP protocol creates an authentication extension, which...
standard protocols, such as the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol (POP), and the Internet Message Access Protocol (IMAP). MIME is...
world's largest selling email system. The Simple Mail Transfer Protocol (SMTP) protocol was implemented on the ARPANET in 1983. LAN email systems emerged...
recipient's ISP. smtp.a.org sends the message to mx.b.org using SMTP. This server may need to forward the message to other MTAs before the message reaches...
base-level IMAP client requires transmitting the message content twice, once to SMTP for delivery and a second time to IMAP to store in a sent mail folder. This...
computers, mobile devices or webmail sites, using the SMTP protocol and either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP)...
also contain spaces and special characters. Using SMTPUTF8 extension of SMTP it is also possible to use non-ASCII characters. Some common sense is needed...
bundling webmail into their service offerings (often in parallel with POP/SMTP services); many other enterprises (such as universities and large corporations)...
before a particular time. The protocol is defined in RFC 3161. One application of the protocol is to show that a digital signature was issued before a...
Transfer Protocol (SMTP) routing aspects, in that it operates on the RFC 5322 message—the transported mail's header and body—not the SMTP "envelope" defined...
the managing director of Techstars in Boston. He was also the chairman of SMTP (company), and a former professional blackjack player with the MIT Blackjack...
network-connected printers. As printer firmware was rarely updated on older models before CHARGEN and other security concerns were known, there may still be many...
the routed or gated daemon. Ultimately, RIP had been extensively deployed before the standard, written by Charles Hedrick, was passed as RIPv1 in 1988. The...
RFC 3207: "SMTP Service Extension for Secure SMTP over Transport Layer Security". Specifies an extension to the SMTP service that allows an SMTP server and...
machine and using container technology. It supports CalDAV, CardDAV and SMTP for messaging, LDAP for directory services, and Microsoft Active Directory...
ISBN 978-0-672-32316-4. Rhoton, J (1999). Programmer's Guide to Internet Mail: SMTP, POP, IMAP, and LDAP. Elsevier. ISBN 978-1-55558-212-8. Voglmaier, R (2003)...
case, performance of Vegas degrades because Vegas reduces its sending rate before Reno, as it detects congestion early and hence gives greater bandwidth to...
hosts[which?] punt mail out of SMTP queue into uucp queues on gateway machines if a .uucp address is recognized on an incoming SMTP connection.[citation needed]...
For example, a host may buffer network data to ensure correct ordering before the data is delivered to an application. IPv4 provides safeguards to ensure...
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