Handbook of Information Security, Volume 1, Key Concepts, Infrastructure, Standards, and Protocols

Internet E-Mail Architecture

Robert Gezelter, Software Consultant

Introduction

Structure

Technology of Synthesis

History

Pre-Internet

User Agents, Protocols, Implementations, and Architectures

Intrasystem Mail

Networked Electronic Mail

Non-Internet Electronic Mail Systems

The Internet

Internet Electronic Mail General Architecture

Applicable RFCs

Dependencies

Mail Handlers

Mail Transfer Agents

Extendibility

Infrastructure Security

Unwanted Commercial Messages

Accountability

Authenticity

Summary

Acknowledgments

Glossary

Cross References

Referencess

Further Reading

INTRODUCTION

Electronic mail was the first mass application, now called a “killer app,” of the networked world. It dominated Internet traffic until the explosion of activity subsequent to the advent of the World Wide Web (WWW; a more complete description of the WWW is provided elsewhere in this Handbook). Many people incorrectly associate electronic mail with the Internet. Electronic mail predates the Internet, and even today there are electronic mail systems that use technologies other than those used on the Internet.

Today's electronic mail landscape is an ecosystem with many inhabitants.

The history of electronic mail is a complex tapestry of give and take among the research, business, academic, and other communities. It is a story of experiments in message content, transport, addressing, composition, and reception.

The original electronic mail concept was modest, providing for transmission of simple text messages. Today, ...