Email Infrastructure and Sending Mechanisms Guide

This guide details the email infrastructure and the mechanisms involved in sending emails. It begins by explaining how an email is sent from a user's perspective, highlighting the role of various protocols and processes that facilitate email delivery. The document outlines the components of email infrastructure, including the Mail User Agent (MUA), Mail Submission Agent (MSA), Mail Transfer Agent (MTA), and Message Delivery Agent (MDA). Each component's function is described, emphasizing the importance of email protocols like SMTP, POP, and IMAP in the delivery process. The guide also discusses the significance of email domains and IP addresses in routing emails effectively. Additionally, it covers the evolution of email, tracing its history from early concepts to modern usage, and explains the different types of email infrastructure that businesses utilize for communication. Understanding these elements is crucial for troubleshooting and optimizing email delivery systems.