{"id":9505,"date":"2021-01-20T07:02:10","date_gmt":"2021-01-20T12:02:10","guid":{"rendered":"http:\/\/local.brightwhiz\/?p=9505"},"modified":"2021-01-20T07:02:10","modified_gmt":"2021-01-20T12:02:10","slug":"smtp-communication-protocol","status":"publish","type":"post","link":"http:\/\/local.brightwhiz\/smtp-communication-protocol\/","title":{"rendered":"What You Need to Know About SMTP Communication Protocol"},"content":{"rendered":"\n

SMTP, also known as Simple Mail Transfer Protocol is an Internet standard that’s a communication protocol for email transmission.<\/p>\n\n\n\n

This protocol is used by mail servers and other message transfer agents (MTAs) to send and receive mail messages. SMTP servers commonly use the Transmission Control Protocol (TCP) on port number 25.<\/p>\n\n\n\n

User-level email clients usually use SMTP communication exclusively for sending messages to a mail server for relaying. Outgoing email to the mail server is usually secured via TLS on port 587 or SSL on port 465 per RFC 8314 standard.<\/p>\n\n\n\n

For retrieving messages, IMAP and POP3 are typically used except for proprietary servers which might often implement proprietary protocols such as Ms. Exchange ActiveSync.<\/p>\n\n\n\n

SMTP Communication Protocol Background<\/h2>\n\n\n\n

SMTP was first defined in 1982 as a delivery protocol only and updated in 2008 with extensions.<\/p>\n\n\n\n

Extensions Support<\/h2>\n\n\n\n

Extended SMTP (ESMTP), Also referred to as Enhanced SMTP, is a definition of protocol extensions to the Simple Mail Transfer Protocol (SMTP) standard that was defined in November 1995 in IETF publication. This defines the general structure for all existing and future extensions. <\/p>\n\n\n\n

ESMTP defines consistent and manageable means by which ESMTP clients and servers can be identified and servers can indicate supported extensions.<\/p>\n\n\n\n